Asteraceae tribe Astereae
Symphyotrichum
American-aster, aster
ascending to erect, rarely vinelike, usually simple, sometimes branched distally, seldom proximally, usually hairy in decurrent lines at least distally, proximally often glabrous, sometimes hairy, sometimes stipitate-glandular distally.
usually cauline, sometimes mostly basal; alternate [opposite, whorled]; usually petiolate, sometimes sessile;
margins entire or dentate to pinnatifid (often gland-dotted, especially in xerophytes).
basal (sometimes persistent to flowering) and cauline;
petiolate (often basal and proximal, sometimes distal, petioles often ± winged, clasping, ciliate) or sessile;
blades (often purplish abaxially, 1, sometimes to 3-nerved) cordate to elliptic, oblanceolate, or spatulate (basal), ovate, elliptic, lanceolate, oblanceolate, or linear (cauline, usually progressively, sometimes abruptly or little reduced distally), margins serrate, crenate, or entire, scabrous or ciliate, faces glabrous or hairy, sometimes stipitate-glandular.
cylindric or campanulate to hemispheric, 4–22 mm diam.
usually flat to conic, sometimes concave, usually epaleate, rarely paleate (often foveolate, socket margins often fimbrillate; paleate in Eastwoodia and Rigiopappus).
flat to slightly convex, pitted, epaleate.
0 or in 1(–2+) series, usually pistillate, rarely neuter or styliferous and sterile;
corollas usually yellow, cyanic, or white (laminae sometimes very reduced, e.g., Conyza spp.).
(8–)12–35(–75+); usually in 1 series, in 2–5 series, rarely in 4–5+ series in S. frondosum, pistillate, fertile;
corollas white, pink, blue, or purple (rays 0, peripheral pistillate florets in 2–5+ series, corollas lacking laminae in sect. Conyzopsis).
0 or (in disciform heads) in 1–3+ series;
corollas usually present, usually yellow, sometimes white, ochroleucous, or reddish to cyanic.
(7–)15–50(–110), bisexual, fertile;
corollas yellow to white, becoming purplish to reddish or pinkish at maturity, ± ampliate, tubes usually shorter than funnelform (cylindric in sect. Conyzopsis) throats, lobes 5, erect, spreading, or reflexed, deltate, triangular, or lanceolate;
style-branch appendages lanceolate.
persistent or falling, usually in 3–5+ series (usually in spirals, sometimes in vertical ranks), distinct, unequal, and herbaceous to chartaceous or scarious or margins and/or apices notably scarious, sometimes in 1–2 series, distinct, subequal, and herbaceous with margins and/or apices barely to notably scarious.
20–84 in (3–)4–6(–9) series, 1(–3)-nerved (not keeled), oblong-lanceolate or oblanceolate or spatulate (outer and mid) to linear (innermost), unequal to subequal, outer sometimes foliaceous, bases usually indurate, margins usually scarious, erose, hyaline or not, (apices usually with a well-defined green zone, sometimes ± foliaceous), faces glabrous or hairy, sometimes stipitate-glandular.
0.
homogamous (discoid; unisexual in Baccharis) or heterogamous (disciform or radiate), usually in corymbiform, paniculiform, racemiform, or spiciform arrays, sometimes borne singly.
radiate or disciform (sect. Conyzopsis), usually in paniculiform, sometimes in racemiform or subcorymbiform arrays, sometimes borne singly.
monomorphic or dimorphic within heads, usually ± columnar to prismatic and 5-ribbed, sometimes compressed and 2-ribbed, rarely beaked, bodies smooth, muricate, ribbed, or rugulose (glabrous or hairy, hairs often glandular);
pappi (rarely 0) usually persistent, usually of barbellulate to barbellate bristles in (1–)2–3+ series, sometimes of scales (scales sometimes aristate), rarely of both scales and bristles or of awns.
usually obovoid or obconic, sometimes fusiform, ± compressed, nerves (2–)3–5(–10, sometimes dark-translucent), faces glabrous or strigillose, eglandular (sparsely stipitate-glandular in S. novae-angliae);
pappi persistent, of (20–)25–40(–55) white to brownish, ± equal, barbellate, apically attenuate bristles in 1(–3) series.
(inner) florets usually bisexual and fertile, rarely functionally staminate (e.g., Benitoa);
corollas usually yellow, sometimes white, ochroleucous, or cyanic, actinomorphic, not 2-lipped, lobes (4–)5;
anther bases obtuse or rounded, not tailed, apical appendages usually triangular to linear, sometimes none;
styles abaxially glabrous and smooth or papillate (distally), branches ± linear, adaxially stigmatic in 2 lines from bases to apices or appendages, appendages usually deltate to lanceolate (abaxially papillate to hispidulous, adaxially smooth, glabrous).
= 8, 7, 5, 13, 18, 21.
Asteraceae tribe Astereae
Symphyotrichum
Almost worldwide; mostly temperate
North America; Mexico; Central America; South America; West Indies; e Eurasia [Introduced in Europe]
Genera 170, species 2800+ (77 genera, 719 species in the flora).
The classification and phylogeny of tribe Astereae has been the object of recent work, both morphologic (K. Bremer 1994; G. L. Nesom 1994, 2000) and molecular (notably the seminal paper by R. D. Noyes and L. H. Rieseberg 1999). Noyes and Rieseberg showed that most genera present in North America belong to a single monophyletic clade, called the North American clade. A series of subsequent studies done in various generic groups or subtribes led to a redefinition of many genera (see literature cited in each genus) and to the transfer of species between genera. The current treatment of the tribe reflects much of these novelties, many presented in a floristic work for the first time. Nesom and H. Robinson (unpubl.) present a worldwide overview of the classification of the tribe.
Large genera such as Erigeron, Symphyotrichum, and Solidago all originated on the continent and subsequently spread to Eurasia or South America. A few genera entered North America from neighboring continents, such as Aster in the strict sense (from Eurasia) or Baccharis (from Central America). A majority of Astereae genera in the flora of North America are endemic to the continent (more so if Mexico were included).
The generic order of the present treatment attempts to reflect the phylogenetic relationships established in recent molecular phylogenetic work.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Species ca. 90 (77, including 1 hybrid, in the flora).
The taxonomy followed here is based partly on G. L. Nesom (1994b, 1997), with the removal or addition of species based on molecular phylogenies (e.g., J. C. Semple et al. 2002; L. Brouillet and S. Selliah 2005).
A. G. Jones (1980) and J. C. Semple and L. Brouillet (1980) proposed classifications of North American asters in which the group now segregated as Symphyotrichum was recognized at various levels. A morphologically based phylogenetic analysis of North American asters was done by Jones and D. A. Young (1983). They identified a group similar to the current Symphyotrichum, but did not segregate it from Aster. G. L. Nesom (1994b, 1997) segregated Symphyotrichum from Aster in a strict sense on a morphologic basis. This segregation was supported by the molecular phylogenetic analysis of R. D. Noyes and L. H. Rieseberg (1999), and confirmed by later data (Semple et al. 2002). Nesom (1994b) provided a summary of the literature on the taxonomy of North American asters.
As here circumscribed, Symphyotrichum excludes members of subtribe Symphyotrichinae with x = 9 (Almutaster, Ampelaster, and Canadanthus), as well as Psilactis (x = 9, 5). These taxa form a grade basal to Symphyotrichum in molecular phylogenies. The genus includes species with x = 8, 7, 5, 13, 18, and 21 (see G. A. Allen 1986), with disploidy to 4 from x = 5. G. L. Nesom (1994b) provided reference to chromosome counts in the genus, and J. C. Semple (1995) reviewed cytologic data. At the present time, karyologic evolution within the genus remains unresolved due to lack of phylogenetic resolution among subgenera and sections in molecular phylogenies. The most basal species appears to be the isolated S. chapmanii (n = 7), a taxon that was unusual in Eurybia (x = 9) on morphologic and cytologic grounds (Semple 1982). Section Conyzopsis also has x = 7; its karyotype is similar to that of x = 8 subg. Symphyotrichum where it is placed. Subgenera Virgulus and Astropolium both have x = 5 (and 4 in the former); their karyotypes differ and currently they do not group in molecular phylogenies. The n = 13, 18, and 21 entities of subg. Ascendentes are polyploids resulting from hybridization between members of subgenera Symphyotrichum and Virgulus in the western United States (Allen 1985, 1986).
Taxonomy of Symphyotrichum is difficult. Species are usually heterophyllous, some strongly so. Individuals in the spring, with basal rosettes, often have leaf shapes quite different from those with cauline leaves seen later in the season. Phyllary shape on first- and later-formed heads may differ. Individuals may vary considerably in plant size and array development depending upon growing conditions. The genetic diversity within each species also appears considerable. Often, plastic or genetic variation have been ascribed mistakenly to hybridization. Nonetheless, hybridization has played a significant role in the taxonomy and evolution of the genus.
J. C. Semple and R. A. Brammall (1982), G. L. Nesom (1994c, 1997) and J. Labrecque and L. Brouillet (1996), among others, discussed Symphyotrichum hybrids. In the x = 8 subg. Symphyotrichum, in particular, interspecific hybridization sometimes renders the taxonomy difficult. In general, sympatric species of the same or of different ploidy levels may produce viable hybrids (e.g., M. L. Dean and K. L. Chambers 1983). Triploid hybrids seem to be generally unviable. Diploid-tetraploid crosses may occur via the production of unreduced gametes in the diploids (Brouillet 1983). Hybridization has led to the evolution of allopolyploid species (e.g., G. A. Allen et al. 1983, Allen 1985, 1986). Allopolyploid species bridge the morphologic gap between diploid entities. In most cases, exact parentage is undetermined, and the placement of some species within sections remains tentative.
Some species have autopolyploid series; for instance the wide-ranging S. lanceolatum has 2n = 32, 40, 48, 56, and 64 (J. C. Semple et al. 1983). Odd levels are the result of inter-cytotype hybridization. The geographic distribution of cytotypes often follows patterns that are interpretable in a geo-historic context (e.g., Semple et al.; A. Legault and L. Brouillet 1989).
On the basis of morphology, cytology, and molecular data, Symphyotrichum is divided into four subgenera. At present, on molecular phylogenetic grounds, all but subg. Symphyotrichum appear to be monophyletic, the exception being the intersubgeneric allopolypoloid subg. Ascendentes. Sections within subg. Symphyotrichum may or may not be monophyletic; relationships among them are still ill-defined and it is not possible to separate morphologically the western sect. Occidentales from the mainly eastern sect. Symphyotrichum with the characters used here. Relationships of sect. Conyzopsis (x = 7) to the western Occidentales have been suggested (e.g., G. L. Nesom 1994b).
In the descriptions below, cespitose refers to plants with clumped stems, colonial refers to plants occuring in more or less extensive clones of stems that are not clumped. Sometimes, plants may be colonial but individuals may have clumped stems, or they may be cespitose with occasional stems farther away at the ends of longer rhizomes.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Key to Genera of Tribe Astereae
1. Trees, shrubs (sometimes clambering, sprawling, or vinelike), or subshrubs | Key A |
1. Annuals, biennials, or perennials | → 2 |
2. Annuals or biennials | Key B |
2. Perennials | Key C |
Key A Trees, shrubs (sometimes clambering, sprawling, or vinelike), or subshrubs
1. Phyllaries unequal and disposed in vertical ranks | → 2 |
1. Phyllaries equal or unequal and disposed in spirals | → 7 |
2. Heads radiate | → 3 |
2. Heads discoid | → 4 |
3. Leaves cauline, blades 1-nerved (sometimes with 1–2 fainter lateral pairs) | Chrysoma |
3. Leaves basal and cauline, blades 3–5-nerved (veins raised, parallel) | Petradoria |
4. Leaves basal and cauline, blades 3-nerved; heads in glomerate clusters grouped in flat-topped, corymbiform arrays; phyllaries yellowish, sometimes green distally | Bigelowia |
4. Leaves cauline, blades 1-nerved (sometimes with 1–2 fainter lateral pairs); heads (sometimes clustered) in paniculiform, corymbiform, or cymiform arrays, or borne singly; phyllaries stramineous, tan, or green, green or purplish distally | → 5 |
5. Leaf faces gland-dotted (in pits); heads in dense, cymiform arrays | Chrysoma |
5. Leaf faces gland-dotted (sessile) or stipitate-glandular; heads borne singly or in condensed, cymiform clusters, grouped in paniculiform or corymbiform arrays, or in congested, cymiform to corymbiform arrays | → 6 |
6. Heads in congested, cymiform to corymbiform arrays; disc florets 4–15; cypselae oblong to obconic | Lorandersonia |
6. Heads borne singly or in condensed, cymiform clusters grouped in paniculiform or corymbiform arrays; disc florets (2–)5–6(–40); cypselae subcylindric | Chrysothamnus |
7. Trees, shrubs (sometimes clambering, sprawling, or vinelike) | → 8 |
7. Subshrubs | → 19 |
8. Plants unisexual, often glutinous; heads discoid | Baccharis |
8. Plants bisexual, sometimes glutinous, gland-dotted, or stipitate-glandular; heads radiate, discoid, or disciform | → 9 |
9. Heads discoid or disciform | → 10 |
9. Heads radiate | → 14 |
10. Heads disciform (pistillate florets 4–9), in compact glomerules grouped in terminal corymbiform arrays; disc corollas orange-yellow; pappi 0, or minute crowns | Gymnosperma |
10. Heads discoid, borne singly, or in clusters grouped in cymiform or racemiform arrays, or in cymiform, spiciform, racemiform, paniculiform, or corymbiform arrays; disc corollas yellow or white; pappi of scales or bristles | → 11 |
11. Cypselae 3–4-angled, strigoso-sericeous; pappi of (5–8) linear-lanceolate scales | Eastwoodia |
11. Cypselae prismatic, terete, subterete, or compressed, glabrous or ± densely hairy; pappi of bristles | → 12 |
12. Stems not resinous; leaves entire or toothed (teeth sometimes bristly); heads usually in spiciform, racemiform, narrowly paniculiform, or corymbiform arrays, rarely borne singly;phyllaries not resinous; pappi reddish brown | Hazardia |
12. Stems resinous; leaves entire; heads borne singly or in clusters (at branch tips), and/or in usually cymiform or racemiform, sometimes paniculiform or thyrsiform arrays; phyllaries resinous; pappi whitish tan to reddish | → 13 |
13. Leaves filiform, linear, lanceolate, or spatulate (adaxially sulcate, concave or plane), margins sometimes undulate or crisped; heads borne singly or in usually cymiform or racemiform, sometimes paniculiform or thyrsiform arrays; involucres hemispheric or obconic; disc florets 4–70, corolla lobes equal (cypselae 2–10 mm) | Ericameria |
13. Leaves filiform, margins flat or involute; heads in clusters at branch tips, grouped in cymiform or racemiform arrays; involucres turbinate; disc florets 3–7, corolla lobes unequal (cypselae 1–3 mm) | Gundlachia |
14. Shrubs clambering, sprawling, or vinelike; rays pale rose-purple to pale pink (Atlantic coastal plain) | Ampelaster |
14. Shrubs not clambering, sprawling, or vinelike; rays yellow or white | → 15 |
15. Plants spinescent (at least with age); corollas yellow | → 16 |
15. Plants not spinescent; corollas white or yellow | → 17 |
16. Leaves sometimes in axillary fascicles; heads borne singly or in loose, corymbiform arrays; ray florets 5–14; disc florets 13–80, bisexual, fertile; pappi of barbellate scales | Acamptopappus |
16. Leaves not in axillary fascicles; heads (2–4) in glomerate clusters, these grouped in corymbiform arrays; ray florets 1–2; disc florets 3–7, functionally staminate; pappi of flattened bristles (those of discs sometimes undulate to twisted) | Amphipappus |
17. Leaves entire or toothed (teeth sometimes bristly; bases clasping or subclasping); heads usually in racemiform, narrowly paniculiform, or corymbiform arrays, rarely borne singly; phyllaries in 5–9 series; cypselae fusiform to deltoid, 4–5-nerved; pappi reddish brown | Hazardia |
17. Leaves entire (bases not clasping); heads borne singly or in cymiform or racemiform (sometimes paniculiform or thyrsiform) arrays; phyllaries in 3–6+ series; cypselae ellipsoid to obconic or obovoid, ± 5–12-ribbed or -nerved; pappi whitish tan to reddish | → 18 |
18. Involucres hemispheric, obconic, or cylindric; disc corolla lobes equal; cypselae prismatic | Ericameria |
18. Involucres turbinate; disc corolla lobes unequal; cypselae± turbinate | Neonesomia |
19. Plants unisexual; heads discoid | Baccharis |
19. Plants bisexual; heads radiate, disciform, or discoid | → 20 |
20. Heads disciform or discoid | → 21 |
20. Heads radiate | → 26 |
21. Stems eglandular; leaves entire | → 22 |
21. Stems gland-dotted or stipitate-glandular; leaves entire, toothed, or pinnatifid | → 23 |
22. Heads borne singly or in cymiform-racemiform arrays; involucres 11–15(–17) mm; florets 4–7; cypselae oblong, 5–6-ribbed, glabrous | Cuniculotinus |
22. Heads borne singly in cymiform arrays; involucres 5–7 mm; florets 12–25+; cypselae narrowly oblong, 8–13-nerved (per face), ± sericeous | Arida |
23. Heads borne singly (at tips of branches) or in corymbiform arrays; cypselae dimorphic (ray ± 3-sided, disc compressed) | Xanthisma |
23. Heads usually in spiciform, racemiform, corymbiform, or cymiform arrays, rarely borne singly; cypselae monomorphic (terete, subterete, or compresssed) | → 24 |
24. Involucres broadly urceolate to hemispheric or globose; phyllaries usually looped to hooked, usually resinous | Grindelia |
24. Involucres campanulate, obconic, turbinate, or cylindric; phyllaries not hooped or hooked, not resinous | → 25 |
25. Basal leaves persistent; heads in compact clusters grouped in corymbiform arrays; involucres 3–9.5 mm; disc corollas goblet-shaped (tubes elongating, elevating throats above involucres at flowering); cypselae obpyramidal, 5–11-ribbed (ribs sometimes thick and resinous), sericeous | Isocoma |
25. Basal leaves withering by flowering; heads in spiciform, racemiform, or cymiform arrays; involucres 11–13 mm; disc corollas ± tubular (tubes not elevating throats); cypselae fusiform to deltoid, 4–5-nerved, glabrous | Hazardia |
26. Rays white, light blue, or purple | → 27 |
26. Rays yellow (sometimes drying red-purple) | → 32 |
27. Plants often thorny (thorns green); leaves usually entire, rarely 1–2-denticulate; heads borne singly or in loose, corymbo-paniculiform arrays; involucres 4.5–7.5 mm; rays white; disc corolla veins orange, resinous | Chloracantha |
27. Plants not thorny; leaves entire, dentate or serrate (teeth spinulose); heads borne singly or in corymbiform arrays; involucres 6–20 mm; rays white, light blue, or purple; disc corolla veins not orange-resinous | → 28 |
28. Cypselae 7–10-nerved, glabrous (Animas River Basin, n New Mexico,s Colorado) | Herrickia |
28. Cypselae 2–7-nerved or -ribbed, hairy | → 29 |
29. Cypselae dimorphic (ray 3-sided, disc compressed), obovoid or oblong | Xanthisma |
29. Cypselae monomorphic (compressed or terete), ovoid, fusiform, cuneiform, or linear | → 30 |
30. Cypselae flattened, 2–(3–4)-nerved; pappi of outer, shorter bristles orscales plus inner, longer bristles | Ionactis |
30. Cypselae ± compressed or not, 4–7-ribbed; pappi of ± unequal bristles (outer not in notably distinct series) | → 31 |
31. Stems glabrous or villous to tomentose, sometimes stipitate-glandular; phyllaries keeled; ray florets bisexual, fertile; cypselae ovoid, fusiform, or linear, 4-nerved, sericeous | Xylorhiza |
31. Stems usually densely white-tomentose, sometimes glabrate or ± stipitate-glandular distally; phyllaries flat; ray florets neuter; cypselae cuneiform or linear, 5–7-ribbed, puberulent to pilose | Corethrogyne |
32. Phyllaries in vertical ranks; heads congested or glomerate, usually in corymbiform or cymiform, sometimes spiciform, arrays | → 33 |
32. Phyllaries in spirals; heads borne singly, 3–6, or glomerate, in flat-topped or multi-storied, corymbiform arrays, or in ± loose corymbiform, racemiform, narrowly paniculiform, or spiciform arrays | → 34 |
33. Leaves basal and cauline (not crowded), 3–5-nerved (veins parallel, raised); heads in glomerules in corymbiform arrays; ray florets 1–3; disc florets functionally staminate, corolla lobes lanceolate; cypselae cylindric, plump orslightly compressed | Petradoria |
33. Leaves cauline (often crowded), usually 1-nerved, sometimes with 1–2 collateral pairs; heads in congested cymiform or corymbiform arrays; ray florets (1–)6–8; disc florets bisexual, fertile; cypselae oblong to obconic or prismatic | Lorandersonia |
34. Involucres usually broadly urceolate, globose, or hemispheric; phyllaries filiform to linear, apices often looped or hooked, faces usually ± resinous | Grindelia |
34. Involucres cylindro-turbinate, turbinate, obconic, campanulate, or hemispheric; phyllaries ovate, lanceolate, oblanceolate, or lanceolate to linear, apices straight or recurved (not looped or hooked), faces sometimes gland-dotted (not resinous). | → 35 |
35. Basal leaves pinnatifid (lobes bristle-tipped); pappi of setiform scales (or basally flattened bristles) | Xanthisma |
35. Basal leaves not pinnatifid; pappi of bristles and/or scales | → 36 |
36. Pappi of scales | Gutierrezia |
36. Pappi of bristles, or of outer, shorter scales plus inner, longer bristles | → 37 |
37. Stems prostrate to erect, mat-forming, branched; leaves cauline (crowded); heads borne singly | Nestotus |
37. Stems erect, not mat-forming, branched or simple; leaves basal and cauline or mostly cauline (then not crowded); heads in spiciform, racemiform, corymbiform, or cymiform arrays, or glomerate and/or pedunculate-solitary in flat-topped or multi-storied, corymbiform arrays | → 38 |
38. Plants rhizomatous; heads usually glomerate, sometimes pedunculate-solitary, in flat-topped or multi-storied, corymbiform arrays | Euthamia |
38. Plants taprooted or fibrous-rooted; heads not glomerate, in spiciform, racemiform, corymbiform, subumbelliform, paniculiform, or cymiform arrays | → 39 |
39. Leaves densely short-woolly (hairs flagelliform); heads in subumbelliform to paniculiform arrays; pappi of outer, triangular scales plus inner bristles in (2–)3 series; e North America | Chrysopsis |
39. Leaves glabrous, sparsely puberulent or stipitate-glandular, or scabroso-hispidulous (hairs not flagelliform); heads in spiciform, racemiform, corymbiform, or cymiform arrays, sometimes borne singly; pappi of unequal bristles in 1–4 series; w North America | → 40 |
40. Leaves basal and cauline, margins entire; involucres cylindro-turbinate; ray florets 5–8; cypselae narrowly oblong, 8-nerved, moderately strigose | Columbiadoria |
40. Leaves mostly cauline, margins serrate (teeth bristle-tipped); involucres campanulate; ray florets 5–18; cypselae fusiform to deltoid, 4–5-nerved, glabrous | Hazardia |
Key B Annuals or biennials
1. Heads discoid or disciform (sometimes radiant) | → 2 |
1. Heads radiate | → 11 |
2. Heads discoid | → 3 |
2. Heads disciform | → 7 |
3. Pappi of (1–)2–10 setiform to subulate scales | → 4 |
3. Pappi 0, or of 3–55 bristles | → 5 |
4. Plants eglandular; heads sessile or subsessile, in secund, spiciform arrays | Thurovia |
4. Plants usually gland-dotted and/or vernicose; heads usually in corymbiform arrays, rarely borne singly | Grindelia |
5. Plants (gracile) 2–14 cm; leaves (linear to filiform) entire; pappi 0, or of (3–)5 bristles or setiform scales | Pentachaeta |
5. Plants (1–)2–100 cm; leaves entire, toothed, or pinnately lobed; pappi of 3–55 bristles | → 6 |
6. Leaf adaxial faces glabrous, puberulent, or canescent; involucres turbinate; phyllaries usually spreading to reflexed, rarely appressed; corollas yellow (limbs of peripheral florets not expanded); pappus bristles white to tawny, distinct | Dieteria |
6. Leaf adaxial faces sparsely tomentose to woolly; involucres hemispheric, obconic, campanulate, or narrowly cylindric; phyllaries erect or recurved; corollas white, pink, lavender, or yellow (limbs of peripheral florets freqently palmately expanded, heads ± radiant); pappus bristles tan to reddish, distinct or connate | Lessingia |
7. Annuals (eglandular); disc corollas without prominent orange veins, style appendages lanceolate or linear | → 8 |
7. Biennials or annuals (usually gland-dotted or stipitate-glandular, sometimes eglandular, in Conyza); disc corollas sometimes with prominent orange veins (Conyza, Erigeron), style appendages deltate | → 9 |
8. Heads borne singly; peripheral pistillate (or reduced ray) florets in 1 series; pappi 0, or of (3–)5 bristles or subulate scales (not surpassing corollas at flowering); grassy areas, chaparral, California | Pentachaeta |
8. Heads in paniculiform arrays (borne singly in small plants); peripheral pistillate florets in 2+ series; pappi of (20–)25–40(–55) bristles (surpassing corollas at flowering); ± saline habitats, edges of ponds, irrigation ditches, salted road-sides, saltmarshes; Rocky Mountains eastward | Symphyotrichum |
9. Biennials; stems ascending; heads borne singly (at ends of branches), disc corolla throats somewhat inflated, white-indurate; pappi of outer, shorter setae plus 15–20 inner, barbellate bristles | Erigeron |
9. Annuals; stems erect; heads usually in corymbiform, paniculiform or racemiform arrays, rarely borne singly; disc corollas narrowly funnelform (throats neither inflated nor indurate); pappi of 10–30 barbellate bristles | → 10 |
10. Leaf faces often stipitate-glandular or gland-dotted; phyllaries lacking orange to brown midnerves; cypselae densely sericeous, ± strigillose, or glabrous, often stipitate-glandular and/or gland-dotted | Laënnecia |
10. Leaf faces eglandular; phyllaries with orange to brownish midnerves; cypselae glabrous or strigillose, eglandular | Conyza |
11. Rays usually yellow or orange, sometimes cream, whitish, or white | → 12 |
11. Rays white, pink, purple, or blue | → 25 |
12. Pappi usually 0, or coroniform, or of scales, rarely of relatively short bristles (Xanthocephalum) | → 13 |
12. Pappi of bristles, or of outer, shorter setae or scales plus inner, longer bristles, or of outer bristles plus inner, subulate to setiform scales | → 17 |
13. Stems and leaves eglandular; phyllaries subequal (± navicular, inner usually each ± enfolding floret); receptacles sparsely paleate between ray and disc florets (paleae resembling phyllaries); ray corollas yellowish, often tinged with red or purple (laminae inconspicuous); disc corolla lobes 2–4 | Rigiopappus |
13. Stems and leaves (at least partly) stipitate-glandular; phyllaries unequal (not navicular nor each enfolding floret); receptacles epaleate; ray corollas yellow to orange-yellow or occasionally suffused with red (laminae conspicuous); disc corolla lobes 5 | → 14 |
14. Disc corollas abruptly ampliate, throats usually campanulate, sometimes funnelform | → 15 |
14. Disc corollas not abruptly ampliate, throats funnelform or cylindric | → 16 |
15. Cypselae terete or slightly compressed with rounded edges or 4–6-sided, without prominent nerves, glabrous or slightly strigose; pappi of rays 0, outer discs 0 or minute crowns, inner 0, or usually of scales, rarely bristles; Arizona, Texas | Xanthocephalum |
15. Cypselae ± triquetrous, 3-nerved, sericeous; pappi of 2–8 subulate, barbellate scales; California | Benitoa |
16. Leaves not glutinous; heads in paniculiform or corymbiform arrays; phyllaries glutinous; disc florets functionally staminate | Amphiachyris |
16. Leaves glutinous; heads borne singly or in clusters of 3–6; phyllaries not glutinous; disc florets bisexual, fertile | Gutierrezia |
17. Stems and leaves usually gland-dotted and/or resinous; involucres usually globose to hemispheric or broadly urceolate, sometimes campanulate or obconic; phyllaries hooked, looped, patent, recurved, straight, or incurved | Grindelia |
17. Stems and leaves usually not resinous, sometimes gland-dotted or stipitate-glandular; involucres hemispheric, campanulate, turbinate, obconic, or cylindric; phyllaries appressed, spreading, reflexed, or recurved | → 18 |
18. Cypselae dimorphic (rays often ± 3-angled, discs ± compressed) | → 19 |
18. Cypselae monomorphic (all ± compressed or all ± 3-angled) | → 21 |
19. Biennials; stems strigose and/or hispid, stipitate-glandular; pappi of rays 0, of discs of outer scales plus 30–45 inner bristles | Heterotheca |
19. Annuals or biennials; stems glabrous or hispid, gland-dotted or stipitate-glandular; pappi of basally flattened bristles (or setiform scales) in 2–4 series | → 20 |
20. Heads borne singly or in corymbiform arrays (peduncles not cobwebby); involucres 4–10 mm; disc corolla throats gradually ampliate, ± funnelform; style-branch appendages lanceolate | Xanthisma |
20. Heads borne singly or (2–3) in paniculiform or subcorymbiform-cymiform arrays (peduncles often cobwebby); involucres 7–16 mm; disc corolla throats abruptly ampliate, funnelform; style-branch appendages deltate | Rayjacksonia |
21. Stems glabrous or glabrate, eglandular; cauline leaves narrowly oblanceolate, linear, or filiform, margins entire, ciliate, faces glabrous or glabrate, eglandular; heads borne singly (at ends of branches); phyllaries not thickened or keeled; rays yellow and often reddish or purplish-tinged | → 22 |
21. Stems ± hispid, pilose, woolly or arachnose, sometimes glabrous, stipitate-glandular or eglandular; cauline leaves ovate, oblanceolate, elliptic, lanceolate, or linear, margins entire, serrate, or apically dentate, sometimes coarsely ciliate, faces usually hairy, sometimes glabrous, sometimes stipitate-glandular; heads borne singly or in corymbiform, subumbelliform, or paniculiform arrays; phyllaries thickened or keeled; ray florets yellow to yellow-orange | → 23 |
22. Involucres campanulate to turbinate; phyllaries equal or subequal; cypselae oblanceoloid, 3–5-nerved, not beaked; pappus bristles (3–)5–20 (usually in multiples of 5) in 1 series | Pentachaeta |
22. Involucres ± cylindric to turbinate or obconic; phyllaries unequal; cypselae ± fusifom, 5-nerved, beaked; pappus bristles (12–)30–40 in (1–)2 series (outer shorter) | Tracyina |
23. Biennials, stems arachnose to woolly or glabrous, often stipitate-glandular; heads in corymbiform, subumbelliform, or paniculiform arrays; pappus bristles relatively fine (mainly Florida, Atlantic coastal plain) | Chrysopsis |
23. Annuals, stems sparsely hispid or pilose, sometimes stipitate-glandular; heads borne singly or in loose paniculiform arrays; pappus bristles relatively thick and rigid, outer sometimes scalelike | → 24 |
24. Leaves 1-nerved, faces hispido-pilose; involucres campanulate, 6–9 mm; phyllaries linear, sparsely stipitate-glandular; cypselae obconic, compressed, smooth or slightly ribbed; Gulf coastal plain, Mississippi embayment, adjacent lowlands | Bradburia |
24. Leaves 3-nerved (nerves ± parallel), faces thin-arachnose (in minute, abaxial lacunae); involucres narrowly turbinate to subcylindric, 4–8 mm; phyllaries lanceolate to linear-lanceolate, eglandular; cypselae turbinate, terete to weakly angled, 6–14-nerved; sc United States, adjacent Mexico | Croptilon |
25. Receptacles conic; pappi 0, or coroniform, or of scales | → 26 |
25. Receptacles flat to convex; pappi usually of bristles (sometimes only discs or rays), or of setiform scales, or of bristles plus scales, or toothed cups with 1 bristle, sometimes of scales, or coroniform, or 0 | → 30 |
26. Leaves usually pinnatifid to dentate, sometimes entire; rays without midstripe abaxially; cypselae not or slightly compressed, glabrous or sparsely strigose (hairs not glochidiform); pappi cartilaginous crowns, or crowns of scales or setae, or 0 | → 27 |
26. Leaves usually entire, sometimes dentate or lobed; rays usually with pink or purplish midstripe abaxially; cypselae strongly compressed or flattened, glabrous or hairy (hairs glochidiform); pappi usually of awns, scales, bristles, or 2-horned crowns, sometimes 0 | → 28 |
27. Plants gland-dotted; cypselae oblong to narrowly obovoid, slightly compressed, 2-nerved, sometimes gland-dotted | Egletes |
27. Plants eglandular; cypselae columnar to prismatic, usually 4-angled, 4–12-ribbed (ribs relatively thick), eglandular | Aphanostephus |
28. Phyllaries in 4–6+ series, unequal; pappi of 12–35+ lanceolate or subulate to setiform scales | Townsendia |
28. Phyllaries in 2(–3) series, subequal; pappi 0, or crowns of setae or scales, or of 2 long plus ring of shorter awns | → 29 |
29. Leaves spatulate-obovate (basal), narrower distally; cypsela margins ribbed; pappi 0, or crowns of setae or scales | Astranthium |
29. Leaves oblanceolate; cypsela margins winglike; pappi of 2 long plususually ring of shorter awns | Dichaetophora |
30. Disc corollas with orange-resinous veins | → 31 |
30. Disc corolla veins not orange-resinous | → 34 |
31. Heads borne singly; pappi crowns (sometimes each with 1 bristle) or of alternating scales and bristles | → 32 |
31. Heads usually in corymbiform or paniculiform arrays, sometimes borne singly; pappi of bristles, or of outer, shorter setae or scales plus inner, longer bristles | → 33 |
32. Phyllaries in 2–6 series, unequal; pappi hyaline crowns (nearly 0) oralternating bristles and scales | Chaetopappa |
32. Phyllaries in 1(–2) series, equal; pappi toothed crowns plus 1 distallyplumose bristle, or of 1–12 bristles alternating with scales | Monoptilon |
33. Disc corolla throats slightly indurate and inflated; pappi usually of outer setae or scales plus 10–30 inner bristles, sometimes 0 | Erigeron |
33. Disc corolla throats not indurate or inflated; pappi of 15–25+ bristles in 1 series | Conyza |
34. Pappi of 12–35+ scales | Townsendia |
34. Pappi of 5–80+ bristles or setiform scales | → 35 |
35. Pappus bristles usually 5, rarely 0 | Pentachaeta |
35. Pappus bristles or setiform scales usually 20–80+ (ray sometimes 0) | → 36 |
36. Stems glabrous or hairy in lines distally, sometimes stipitate-glandular distally; leaf margins entire, subserrate, serrate, or pinnately lobed; heads usually in paniculiform or corymbiform arrays, sometimes borne singly | → 37 |
36. Stems hairy or glabrous, sometimes stipitate-glandular; leaf margins entire, serrate, dentate, laciniate, lobed, or ± deeply 1–2-pinnatifid (teeth or lobes apiculate, bristly, or spiny); heads borne singly (at ends of branches) or in cymiform or corymbiform arrays | → 38 |
37. Stems distally stipitate-glandular; cauline leaf bases clasping to subclasping, margins entire, coarsely toothed, or pinnately lobed, faces appressed-hairy or glabrous (distal stipitate-glandular); heads in corymbiform arrays; involucres broadly turbinate to hemispheric; phyllaries herbaceous distally, stipitate-glandular; ray florets 20–70 in 1 series, corollas white, blue, or purple; pappi: rays 0, discs of bristles | Psilactis |
37. Stems eglandular; cauline leaf bases attenuate, cuneate, or rounded, margins entire or serrulate, faces glabrous, eglandular; heads in paniculiform arrays; involucres cylindro-campanulate, cylindric, or turbinate; phyllaries with distinct green zones distally, eglandular; ray florets 16–54 in 1–3 series, or 90–110 in 4–5 series, corollas white, pink, or lavender; pappi of bristles | Symphyotrichum |
38. Leaves deeply 1–2-pinnatifid, at least many lobes or teeth acute and bristly | Machaeranthera |
38. Leaves entire or toothed or lobed, if 1–2-pinnatifid, teeth or lobes often rounded, sometimes apiculate, mostly not bristly | → 39 |
39. Plants hairy, sometimes stipitate-glandular; leaves entire or toothed; ray pappi of 40–50 bristles | Dieteria |
39. Plants glabrous and leaves entire or toothed (ciliate or teeth bristle-tipped or apiculate), or plants hairy, sometimes stipitate-glandular, and leaves 1–2-pinnatifid; ray pappi usually 0 (if 20–30 bristles, leaves 1–2-pinnatifid) | Arida |
Key C Perennials
1. Heads discoid or disciform | → 2 |
1. Heads radiate | → 18 |
2. Heads disciform | → 3 |
2. Heads discoid | → 5 |
3. Cauline leaf margins entire or spinulose-serrate; heads borne singly or 2–3 in ± corymbiform arrays; cypselae subcylindric-fusiform, 3–4-angled, ± compressed, with 10–12 faint nerves; pappi of 15–60 rigid, unequal, smooth bristles in 1 series | Pyrrocoma |
3. Cauline leaf margins entire, dentate, or pinnatifid (lobed); heads in corymbiform arrays; cypselae oblong or oblong-obovoid to elliptic or obovoid, ± compressed or flattened, 2(–4)-nerved or ± nerved on edges; pappi of outer setae or scales plus 5–40 bristles, or of 30–40+ bristles in 2 series (outer usually shorter) | → 4 |
4. Plants ± densely white-tomentose (at least some surfaces); phyllaries 1-nerved, nerves not golden-resinous; disc corollas yellowish, throats narrowly funnelform, not indurate, veins light, not resinous; pappi of 30–40+ bristles in 2 series (outer usually shorter) | Laënnecia |
4. Plants ± hirsute or pilose; phyllaries usually 1–3-nerved, nerves golden-resinous; disc corollas yellow, strongly constricted basally, throats sometimes strongly inflated-indurate, nerves often orange-resinous; pappi of outer setae (or 0) plus 7–25 inner bristles | Erigeron |
5. Disc corollas white or pale yellow; pappi of 10 basally connate scales | Thurovia |
5. Disc corollas yellow (white in Brintonia); pappi usually of distinct bristles or of outer, shorter setae or scales plus inner, longer bristles, sometimes 0 | → 6 |
6. Stems and leaves resinous, gland-dotted; phyllary apices hooked or looped, or slightly recurved to straight; pappi of 2–8 bristles | Grindelia |
6. Stems and leaves sometimes resinous, sometimes stipitate-glandular or gland-dotted; phyllary apices straight to squarrose; pappi of 10+ bristles | → 7 |
7. Phyllary midveins translucent and swollen at least basally (not resinous) | → 8 |
7. Phyllary midveins usually not notably swollen (orange-resinous in Erigeron) | → 9 |
8. Disc corollas white | Brintonia |
8. Disc corollas yellow | Solidago |
9. Phyllary and corolla nerves orange-resinous; pappi of outer, shorter setae or scales plus inner, longer bristles | Erigeron |
9. Phyllary and corolla nerves not orange-resinous, or only corolla nerves orange-resinous; pappi of equal or unequal bristles. | → 10 |
10. Phyllaries subequal, foliaceous | Toiyabea |
10. Phyllaries unequal (sometimes subequal, then outer not foliaceous), outer ± herbaceous (sometimes foliaceous), or chartaceous, or proximally indurate | → 11 |
11. Phyllaries keeled, distally only with relatively small green zones or green along midveins; pappus bristles in 2–3 series (outer in notably shorter series or relatively few) | → 12 |
11. Phyllaries usually flat, sometimes keeled, distally herbaceous or green; pappi of equal or unequal bristles in 1–3 series (outer not in notably shorter series) | → 13 |
12. Leaves cauline (proximal withering by flowering), margins without coarse spreading cilia near bases; phyllary margins often reddish, sometimes hyaline, abaxial faces glabrous or glabrate to woolly, sometimes stipitate-glandular | Eucephalus |
12. Leaves basal and cauline (basal and proximal withering by flowering), margins with coarse spreading cilia near bases or on petioles; phyllary margins not reddish, scarious, abaxial faces ± hispid or stipitate-glandular | Heterotheca |
13. Leaf faces densely scabrous and short-stipitate-glandular; phyllaries ± keeled proximally (Esmeralda County, Nevada) | Tonestus |
13. Leaf faces glabrous or canescent, ± puberulent, hispidulous, tomentose, or villous, and/or sometimes ± stipitate-glandular or gland-dotted; phyllaries sometimes keeled | → 14 |
14. Leaves basal and cauline, basal and proximal petiolate, distal sessile; disc floret style appendages lanceolate | → 15 |
14. Leaves cauline, sessile; disc floret style appendages triangular | → 16 |
15. Plants densely stipitate-glandular, with caudices; stems densely clustered, simple; leaf blades obovate or oblong to broadly oblanceolate; phyllaries keeled; disc corolla throats cylindric; cypselae white strigoso-hirsute | Triniteurybia |
15. Plants sparsely, if at all, stipitate-glandular, taprooted; stems single, usually branched; leaf blades lanceolate to oblanceolate; phyllaries flat; disc corolla throats funnelform; cypselae sparsely appressed-hairy | Dieteria |
16. Phyllary margins scarious; disc corolla lobes unequal; cypselae obpyramidal, sericeous; pappi of 40–50 tawny bristles | Isocoma |
16. Phyllary margins not scarious; disc corolla lobes equal; cypselae prismatic, narrowly turbinate, fusiform, or deltoid, glabrous or sparsely scabrous; pappi of 15–30 reddish brown to brownish bristles | → 17 |
17. Stems glabrous or scabrous, eglandular; leaf bases not subclasping, margins entire; cypselae prismatic or narrowly turbinate; pappus bristles barbellate | Oönopsis |
17. Stems scabrous to sparsely tomentulose, distally stipitate-glandular; leaf bases subclasping, margins serrate; cypselae fusiform to deltoid; pappus bristles smooth | Hazardia |
18. Rays usually yellow or orange, sometimes cream-colored or white | → 19 |
18. Rays white, pink, purple, or blue | → 38 |
19. Pappi 0, or crowns, or of scales | → 20 |
19. Pappi of bristles, or of outer shorter setae, bristles, or scales plus inner, longer bristles, or of setiform awns. | → 21 |
20. Leaves cauline (basal withering by flowering), blades linear to lanceolate or spatulate, stipitate-glandular; heads borne singly or in clusters of 3–6; phyllaries in 2–4 series; cypselae clavate or cylindric, not compresssed, 5–8-nerved, white-hairy (hairs clavate to bulbous); pappi usually of 5–10 scales, sometimes crowns or 0 | Gutierrezia |
20. Leaves basal (present at flowering) and cauline, blades spatulate, eglandular; heads borne singly (± sessile); phyllaries in 3–7+ series; cypselae obovoid to lanceoloid, flattened, 2-nerved, hairy (hairs glochidiform); pappi of 10–12 (ray) or 20–35+ (disc), lanceolate to subulate or setiform scales | Townsendia |
21. Pappi of outer shorter setae, bristles, or scales plus inner, longer bristles in 2 series | → 22 |
21. Pappi of setiform scales or bristles in 1–4 series | → 26 |
22. Plants taprooted or with simple caudices (and fibrous-rooted); heads borne singly or in 2s or 3s; phyllaries in 2–3 series, equal or subequal, flat, usually 1–3-nerved (nerves golden-resinous); cypselae 2-nerved, not resinous | Erigeron |
22. Plants taprooted, rhizomatous, or with branched caudices; heads in corymbiform, ± paniculiform, or subumbelliform arrays, sometimes borne singly; phyllaries in 3–5 series, unequal, usually thickened or keeled (not in Bradburia), 1-nerved, not golden-resinous; cypselae smooth or 1–14-nerved or -ribbed, nerves or ribs sometimes resinous | → 23 |
23. Stems and leaves silky-sericeous, rarely glabrate; leaves sessile, blades 3–11-parallel-nerved (nerves sunken), linear to lanceolate or ovate (often grasslike), margins entire; involucres turbinate | Pityopsis |
23. Stems and leaves whitish-strigose, pilose, hispid, or arachnose to woolly (hairs flagelliform, soft), or glabrous; leaves sessile or basal petiolate, blades usually 1-nerved (veins reticulate, raised abaxially), spatulate, ovate-oblanceolate, ovate, elliptic, elliptic-oblong, oblanceolate, linear-lanceolate, or (usually distal) linear, margins entire, serrate, or dentate (sometimes coarsely ciliate); involucres campanulate or turbinate | → 24 |
24. Plants proximally woolly, distally arachnose or pilose (hairs flagelliform); basal leaves sessile | Chrysopsis |
24. Plants sparsely to ± densely hispid, strigose, or pilose (hairs not flagelliform); basal leaves petiolate | → 25 |
25. Perennials (taproots relatively short and/or caudices woody); basal petioles ciliate; cauline leaves much reduced distally, not clasping; heads borne singly or in lax paniculiform arrays; cypselae monomorphic, ray pappi of outer, shorter, setiform scales or bristles plus inner, longer bristles | Bradburia |
25. Perennials (caudices woody); basal petioles long-strigoso-ciliate; cauline leaves ± reduced distally, sometimes clasping or subclasping; heads borne singly or in corymbiform, sometimes paniculiform arrays; cypselae dimorphic or monomorphic, ray pappi 0, or of outer, linear-lanceolate scales plus inner, longer bristles | Heterotheca |
26. Stems and leaves resinous, gland-dotted; involucres usually globose, hemispheric, or broadly urceolate, sometimes campanulate to obconic, usually ± resinous; pappi of (1–)2–8 white, straight, contorted, or curled, barbellate or smooth awns or setiform scales in 1 series | Grindelia |
26. Stems and leaves usually not resinous, sometimes stipitate-glandular or gland-dotted; involucres hemispheric, campanulate, turbinate, or cylindric, not resinous, sometimes viscid or stipitate-glandular or gland-dotted; pappi of white, tawny, brownish, or reddish, barbellate bristles in 1–4 series | → 27 |
27. Plants ± colonial (rhizomatous); heads usually glomerate, and/or sometimes pedunculate-solitary in flat-topped or multi-storied, corymbiform arrays | Euthamia |
27. Plants colonial (sometimes rhizomatous, stems single or clustered, usually from ± woody taproots or caudices); heads borne singly, or (2–5) in paniculiform to corymbiform arrays, or in open or dense corymbiform, paniculiform (diversely shaped in Solidago), racemiform, or spiciform arrays (if glomerate, not in flat-topped, corymbiform arrays, arrays not storied) | → 28 |
28. Plants rhizomatous (often colonial); heads in dense corymbiform or paniculiform arrays | → 29 |
28. Plants usually taprooted or with caudices, sometimes also from spreading roots (stems single or clustered); heads usually borne singly, sometimes (2–5) in loose corymbiform, cymiform, or paniculiform arrays, or in spiciform, racemiform, paniculiform, or corymbiform arrays, or glomerate (some Oönopsis) | → 30 |
29. Stems and leaves sometimes stipitate-glandular or gland-dotted; cauline leaf bases not clasping, faces sometimes resinous; heads in rounded, club-shaped, wand-shaped, or pyramid-shaped paniculiform (often secund) arrays, or in flat-topped, corymbiform arrays; involucres campanulate to cylindric, 3–12 mm, sometimes stipitate-glandular; phyllary midveins usually swollen, translucent, apices often with green zone, sometimes reflexed; ray florets 3–15(–21); disc corolla lobes lanceolate, erect to reflexed, style-branch appendages triangular; cypselae obconic, terete or ± compressed, 5–8-nerved; pappi of unequal bristles in 1–2(–3) series | Solidago |
29. Stems and leaves stipitate-glandular; cauline leaf bases clasping or subclasping, faces resinous; heads in dense, flat-topped, corymbiform arrays; involucres campanulate to hemispheric, 10–11 mm, stipitate-glandular; phyllary midveins not swollen, apices green-tipped and spreading-reflexed; ray florets 12–20; disc corolla lobes triangular, spreading, style-branch appendages linear; cypselae fusiform, distinctly compressed, 12–16-nerved (nerves whitish, raised); pappi of equal bristles in 2(–3) series; w United States | Oreochrysum |
30. Stems sometimes clustered; heads usually in rounded, club-shaped, wand-shaped, or pyramid-shaped, paniculiform, or flat-topped, corymbiform (often secund) arrays, or in spiciform, racemiform, or cymiform arrays, sometimes borne singly | → 31 |
30. Stems single or clustered; heads borne singly or (2–5) in loose, corymbiform or paniculiform arrays, or 2–5(–15) in racemiform, spiciform, or corymbiform arrays | → 32 |
31. Plants with caudices (stems clustered); leaves basal and cauline; heads in rounded, club-shaped, wand-shaped, or pyramid-shaped, paniculiform (often secund) or flat-topped corymbiform arrays; involucres campanulate to cylindric, 3–12 mm; phyllary midveins usually swollen and translucent; cypselae 5–8-nerved | Solidago |
31. Plants taprooted; leaves mostly cauline; heads usually in spiciform, racemiform, or cymiform arrays, sometimes borne singly; involucres campanulate, 11–13 mm; phyllary midveins not swollen; cypselae 4–5-nerved (California, Oregon) | Hazardia |
32. Stems single, usually branched; cypselae dimorphic (rays 3-angled, discs ± compressed), obovoid, oblong, or obscurely cordate, or rays broadly ellipsoid to obovoid (thick-walled) and discs broadly ellipsoid to clavate (thin-walled); pappi of coarse, barbellate bristles or setiform scales | → 33 |
32. Stems single or clustered, usually simple; cypselae monomorphic, terete or compressed to ± flattened, prismatic (3–4-angled), narrowly turbinate, subcylindric-fusiform, cylindric, or linear (usually thin-walled); pappi of relatively fine barbellate bristles | → 34 |
33. Basal leaves 1–2-pinnatifid, cauline deeply incised to coarsely dentate or ± entire; involucres 6–10 mm; phyllaries stiff, leathery or bases indurate, apices herbaceous; disc corolla throats not abruptly ampliate, style-branch append-ages lanceolate | Xanthisma |
33. Leaves linear to oblanceolate, coarsely serrate to entire; involucres 7–16 mm; phyllaries herbaceous; disc corolla throats abruptly ampliate, style-branchappendages deltate | Rayjacksonia |
34. Leaves 3-nerved, faces arachnose (in minute, abaxial lacunae); involucresnarrowly turbinate to subcylindric; pappi tawny to reddish brown | Croptilon |
34. Leaves 1–3(–5)-nerved, faces glabrous, scabrous, villous, sericeous, tomentose, or lanate; involucres hemispheric to broadly or narrowly campanulate; pappi whitish or brownish | → 35 |
35. Plants sometimes mat-forming; stems clustered; leaves 1–5-nerved; margins of outer phyllaries scarious; pappi whitish | → 36 |
35. Plants not mat-forming; stems single or clustered; leaves 1-nerved; margins of outer phyllaries herbaceous (sometimes proximally indurate); pappi brownish | → 37 |
36. Stems eglandular or stipitate-glandular, sometimes resinous; leaf margins entire, faces glabrous, scabrous, villous, or lanate, usually stipitate-glandular, sometimes eglandular; phyllaries unequal, proximally indurate, distally chartaceous or herbaceous; ray florets 5–17; cypselae usually sericeous, sometimes glabrous | Stenotus |
36. Stems densely stipitate-glandular (viscid); leaf margins entire, coarsely and irregularly serrate, dentate, or lobed, faces glabrous or scabrous, sometimes stipitate-glandular; phyllaries subequal, outer foliaceous; ray florets 11–23(–35); cypselae glabrous or villous | Tonestus |
37. Stems and leaves glabrous or sparsely tomentose, eglandular; leaves basal (usually withering by flowering) and cauline, blades narrowly oblanceolate to lanceolate or linear, margins entire; heads borne singly, or 2–12 in glomerules or in loose, corymbiform arrays (subtended by little-reduced distal leaves); rays 6–25; cypselae prismatic or narrowly turbinate | Oönopsis |
37. Stems and leaves loosely tomentose to woolly, sometimes gland-dotted or stipitate-glandular; leaves basal (persistent) and cauline, basal blades oblanceolate to elliptic or linear, cauline lanceolate, margins entire, spinulose-dentate or -serrate, or shallowly laciniate; heads borne singly or (2–15, ± sessile) in racemiform, spiciform, or loose, corymbiform arrays (at ends of scapiform stems or peduncles); rays 10–80; cypselae subcylindric-fusiform | Pyrrocoma |
38. Receptacles conic; rays white (pink or purplish-tinged abaxially) | → 39 |
38. Receptacles flat or convex; rays white, pink, blue, or purple (not tinged abaxially) | → 40 |
39. Plants 5–20 cm (scapiform, short-rhizomatous); leaves mostly basal, margins crenate-serrate; phyllary margins herbaceous; rays in 3–4 series (closing at night); cypselae obconic, compressed, margins thickened, riblike, apices not cupped; pappi 0 | Bellis |
39. Plants 5–50 cm (leafy, taprooted); leaves basal and cauline, margins entire or toothed to pinnatifid; phyllary margins broadly scarious; rays in 1(–2) series (not closing at night); cypselae columnar, usually 4-angled, 4–12-ribbed, apices usually cupped; pappi of awns, aristate scales, short bristles, or 0 | Aphanostephus |
40. Plants colonial; stems branched (lateral branches strongly ascending, commonly modified to green thorns); leaves early withering; phyllaries (1–)3(–5)-nerved (usually wet sites in arid, sw United States) | Chloracantha |
40. Plants sometimes colonial; stems single or clustered, simple or branched (not becoming thorny); at least distal leaves persistent through flowering; phyllaries usually 1-nerved, seldom 3-nerved | → 41 |
41. Cypselae usually obconic or obovoid, sometimes lanceoloid, flattened or compressed, margins ribbed (sometimes 1–2 nerves also on faces) | → 42 |
41. Cypseale ± narrowly obconic, obovoid, oblanceoloid, lanceoloid, fusiform, or linear, ± compressed or terete, sometimes winged or wings reduced and resembling marginal nerves or ribs (then pappi 0 or of minute scales), usually 3–12+-nerved on faces (margins not ribbed) | → 46 |
42. Leaves cauline; phyllaries keeled | → 43 |
42. Leaves basal and/or cauline; phyllaries not keeled | → 44 |
43. Plants 10–160 cm, minutely stipitate-glandular distally; proximalmost leaves scalelike, proximal withering by flowering, cauline distally increasing in size to mid stems, mid and distal blades lanceolate or lance-ovate to elliptic; heads in racemiform or corymbiform arrays; cypselae glabrous, pilose, or strigose, eglandular; pappi of outer, shorter plus inner, longer bristles in 3 series | Eucephalus |
43. Plants 4–30(–70) cm, sometimes stipitate-glandular; leaves persistent to flowering, mostly equal in size and shape, blades spatulate (proximal), linear, narrowly oblong, or elliptic-lanceolate; heads borne singly or in 2s or 3s, or in corymbiform arrays; cypselae densely strigose or sericeous, sometimes stipitate-glandular; pappi of outer shorter bristles or scales plus inner, longer bristles in 2 series | Ionactis |
44. Leaf faces eglandular; corolla lobes lanceolate; pappi of 20–30 bristles | Aster |
44. Leaf faces often gland-dotted; corolla lobes deltate or lance-deltate; pappi usually of 12–35+ scales, or of outer setae or scales plus 5–40(–50) bristles (sometimes only on rays or on discs), sometimes 0 | → 45 |
45. Plants taprooted or with branched caudices; heads borne singly; leaves usually entire, rarely toothed or lobed; phyllaries unequal, 1-nerved (nerves not golden-resinous); disc corolla throats funnelform; cypselae glabrous or hairy (hairs glochidiform); pappi of 12–35+ scales | Townsendia |
45. Plants rhizomatous, sometimes taprooted; heads borne singly or in corymbiform arrays; leaves entire, ± dentate, or pin-natifid; phyllaries equal to unequal, 1–3-nerved (nerves golden-resinous); disc corolla throats sometimes strongly inflated-indurate; cypselae glabrous, strigose, or sericeous; pappi usually of outer, shorter setae or scales plus 5–40(–50) inner, longer bristles (sometimes only on rays or discs),sometimes 0 | Erigeron |
46. Pappi 0, or crowns of setae or scales, or of scales, of alternating scales and bristles, or of outer, shorter setae or scales plus inner, longer bristles | → 47 |
46. Pappi of bristles or setiform scales | → 50 |
47. Phyllary midnerves not swollen, not orange-resinous; disc style-branch appendages triangular or lanceolate | → 48 |
47. Phyllary midnerves (or 1–3 nerves) orange-resinous; disc style-branch appendages deltate | → 49 |
48. Leaves usually entire, sometimes dentate or lobed, bases clasping or subclasping; phyllaries subequal; pappi rings or crowns of setae or scales | Astranthium |
48. Leaves entire, bases not clasping; phyllaries unequal; pappi thickened rings, crowns of scales (basally fused or distinct), or minute outer scales plus inner bristles | Chaetopappa |
49. Plants not colonial (stems ± clustered), stems and leaves stipitate-glandular; basal leaves persistent or withering by flowering; heads borne singly or (2–10) in corymbiform arrays; pappi usually of outer setae or scales plus 5–40(–50) inner bristles, sometimes 0 | Erigeron |
49. Plants colonial, stems and leaves eglandular; basal leaves withering by flowering; heads in corymbiform or diffuse, paniculiform arrays; pappi of 2–3 awns plus shorter bristles or scales, or wholly of minute scales | Boltonia |
50. Cypselae ± dimorphic (ray 3-sided and rounded abaxially, disc ± compressed); pappi of relatively coarse (± flattened) bristles or setiform scales | → 51 |
50. Cypselae monomorphic; pappi of relatively fine bristles | → 52 |
51. Stems simple; leaves mostly basal, margins serrate or serrulate; involucres depressed-hemispheric; cypselae 3–9-ribbed on each face; pappus bristles coarsely barbellate | Xanthisma |
51. Stems usually branched; leaves basal (persistent in rosettes or withering) and cauline (distally ± reduced) or mostly cauline, margins pinnately lobed or pinnatifid, toothed, or entire; involucres turbinate, campanulate, or hemispheric; cypselae 8–13-nerved on each face; pappus bristles barbellulate | Arida |
52. Plants mostly rhizomatous, sometimes with caudices; heads in paniculiform or racemiform arrays, rarely borne singly | → 53 |
52. Plants taprooted, with caudices, or rhizomatous; heads in corymbiform (or flat-topped racemiform) arrays or borne singly, or sometimes grouped into loose corymbiform arrays | → 56 |
53. Stems spreading-hirsute, eglandular; heads in narrow (wand-shaped), paniculiform arrays; phyllary midribs translucent and swollen; rays 7–9, corollas white to pale cream | Solidago |
53. Stems usually glabrous, often distally hairy in lines, sometimes ± densely hairy, sometimes distally stipitate-glandular; heads in ± open or dense (not wand-shaped), paniculiform arrays; phyllary midnerves not translucent and swollen; rays (8–)12–65(–75), corollas white, pink, blue, or purple | → 54 |
54. Phyllaries usually unequal, sometimes subequal, proximally indurate, distally with defined green zone, sometimes distally foliaceous, or outer whollyfoliaceous, sometimes short-stipitate-glandular | Symphyotrichum |
54. Phyllaries subequal, herbaceous (without definite distal green zones, not foliaceous), short-stipitate-glandular | → 55 |
55. Stems ± densely villous; leaves cauline, blades 1-nerved (venation reticulate), lanceolate to elliptic, bases auriculate-clasping, abaxial faces glabrate to ± strigose, adaxial sparsely villous (distal stipitate-glandular); phyllaries often purplish, apices of outer acuminate; disc corollas whitish to pale yellow; cold wet soils, montane (n Cordilleras) and boreal North America | Canadanthus |
55. Stems glabrous; leaves basal and cauline, blades 3-nerved (nerves ± parallel), linear, bases subclasping, faces glabrous (distal stipitate-glandular); phyllaries green, apices of outer acute; disc corollas yellow; damp alkaline areas, deserts and dry prairies, w North America | Almutaster |
56. Plants usually tapooted, sometimes with caudices (also rhizomatous from fibrous roots in Chaetopappa); stems usually 1 (sometimes 2–5+ in clusters), branched or simple; heads borne singly or in loose corymbiform arrays | → 57 |
56. Plants rhizomatous or with caudices; stems 1–5+, usually simple; heads usually in corymbiform arrays, sometimes borne singly (then plants long-rhizomatous, rays pink) | → 62 |
57. Stems and leaves usually densely white-tomentose, sometimes glabrate, stipitate-glandular or gland-dotted; stems simple; ray florets neuter; cypselae cuneiform or linear; pappi reddish to brownish (bristles relatively coarse, California) | Corethrogyne |
57. Stems and leaves glabrous, glabrate, canescent, villous, or tomentose, sometimes stipitate-glandular or gland-dotted; stems simple or branched; ray florets pistillate, fertile; cypselae fusiform, cylindric, obovoid, or linear; pappi hyaline or white to tawny | → 58 |
58. Stems simple; leaf margins entire; phyllaries mostly foliaceous (margins sometimes proximally indurate); rays white (maturing or drying bluish or purplish) | → 59 |
58. Stems branched or simple; leaf margins entire or toothed (teeth apiculate, ± spinulose, or spine-tipped); phyllaries usually not foliaceous (proximally white-indurate, distally green or herbaceous); rays white, blue, violet, or purple | → 60 |
59. Leaves basal and cauline (crowded), blades linear-oblanceolate to lanceolate, 1-nerved; phyllaries not keeled; cypselae 5-nerved | Chaetopappa |
59. Leaves mostly basal (rosettes), blades linear to oblanceolate, 3-nerved; phyllaries often ± keeled; cypselae 5–10-nerved (nerves raised) | Oreostemma |
60. Stems mostly simple (scapiform); leaves mostly basal (rosettes, often marcescent), margins entire or irregularly serrate (teeth apiculate or ± spinulose); phyllaries squarrose; cypselae 8–10-ribbed (canyons, rock faces, Utah) | Herrickia |
60. Stems mostly branched; leaves basal and cauline, margins entire or toothed (teeth spinose-tipped); phyllaries appressed, spreading, or reflexed; cypselae 4-nerved, 4–6-ribbed, or smooth | → 61 |
61. Stems mostly single; cauline leaf blades lanceolate to oblanceolate; phyllaries not keeled | Dieteria |
61. Stems clustered; cauline leaf blades spatulate to obovate oroblong, rarely elliptic; phyllaries keeled | Xylorhiza |
62. Phyllaries flat, not keeled, midveins orange-resinous or swollen and translucent | → 63 |
62. Phyllaries ± rounded, sometimes ± keeled, midveins not swollen | → 64 |
63. Plants 40–200 cm; leaves basal (not persistent, reduced) and cauline, blades 1-nerved (venation brochidodromous), lanceolate to elliptic; phyllary midveins orange-resinous; rays 2–10(–16) | Doellingeria |
63. Plants 10–40 cm; leaves basal (persistent, well developed) and cauline (reduced), blades usually 1-nerved, sometimes ± 3-nerved (venation reticulate), linear to linear-lanceolate, phyllary midveins swollen, translucent; ray florets 10–20 | Solidago |
64. Plants rhizomatous and/or with woody caudices (rhizomes with swollen apical buds); heads in ± loose, corymbiform arrays or borne singly (nodding in bud); phyllaries lance-ovate to linear (membranous), proximally not indurate, green along midnerves; cypselae 5–8-nerved (lateral 2 thicker), glabrous, ± densely gland-dotted; e North America | Oclemena |
64. Plants rhizomatous (rhizomes not apically swollen) and/or with caudices; heads in corymbiform arrays (erect in bud); phyllaries ovate, oblong, lanceolate, or linear-lanceolate, proximally indurate, distally with sharply delimited green apical zones; cypselae 7–12(–18)-nerved, glabrous, strigillose, or strigose, eglandular; e, w North America (excluding United States prairies) | → 65 |
65. Involucres cylindric; ray florets 1–6, white; disc corollas white or cream-colored; cypselae ± densely strigose | Sericocarpus |
65. Involucres cylindro-campanulate or campanulate; rays 5–60, white to purple; disc corollas yellow; cypselae glabrous or ± densely strigillose | → 66 |
66. Stems and leaves usually stipitate-glandular, sometimes eglandular and glaucous; leaves mostly cauline, entire or spinulose-serrate, glabrous or scabrellous; phyllaries sometimes rounded, usually keeled, apices acuteto long-acuminate; rays 8–27; disc corolla tubes shorter than limbs (w Cordilleras) | Herrickia |
66. Stems and leaves usually eglandular, sometimes stipitate-glandular (e North America only), not glaucous; leaves basal and/or cauline, serrate (teeth sometimes spinulose or spinose, blades then linear, grasslike, se North America) or entire, hairy or glabrous; phyllaries usually rounded, sometimes keeled, apices obtuse to acute; rays 5–60; disc corolla tubes shorter or longer than limbs | Eurybia |
1. Annuals (ray or pistillate florets in 1–5 series) | → 2 |
1. Perennials (ray florets usually in 1 series, in 4–5+ series in S. frondosum) | → 5 |
2. Ray florets 16–30(–54) (in 1–3 series, laminae 0.2–1.3 mm wide); phyllaries unequal, green zones lanceolate (covering at most distal portion) | S. subulatum |
2. Ray (or pistillate) florets (14–)75–110+ (in 2–5+ series, laminae 0 or 0.1–0.2 mm wide); phyllaries subequal, outer foliaceous, green zones of inner lanceolate (sect. Conyzopsis) | → 3 |
3. Ray florets 90–110+ (laminae 4.5–5 × 0.1–0.2 mm); w of Rocky Mountains | S. frondosum |
3. Pistillate florets 14–95 (laminae 0); mostly e of Rocky Mountains, Alaska, Yukon | → 4 |
4. Leaf and phyllary margins ciliate; plants 7–70+ cm; leaf apices acute to short-acuminate; cypselae hirsuto-strigose; moist, saline areas in prairies and steppes,irrigation ditches, tidal marshes (Hudson Bay) | S. ciliatum |
4. Leaf and phyllary margins eciliate; plants 2–30+ cm; leaf apices obtuse; cypselae glabrous; tidal marshes, Gulf of St. Lawrence | S. laurentianum |
5. Ray laminae 0.1–0.2 mm wide | S. frondosum |
5. Ray laminae 0.5–2.5 mm wide | → 6 |
6. Ray corollas usually white, sometimes purplish or pinkish-tinged | → 7 |
6. Ray corollas violet, purple, blue, lavender, or pink (sometimes pale; white-rayed individuals occur in most species) | → 32 |
7. Stems sparsely to densely hairy, sometimes glabrescent proximally | → 8 |
7. Stems glabrous or glabrate to sparsely puberulent (usually hairy in lines distally, at least in arrays). | → 13 |
8. Phyllary apices spine-tipped (spines white or clear) | → 9 |
8. Phyllary apices (flat or involute or folded and green) not spine-tipped | → 10 |
9. Involucres 2.5–4.5(–5) mm; ray florets (8–)10–18(–20), laminae 6–12(–20) mm; disc corollas 2.5–4 mm, lobes 0.5–0.6; cypselae 1.2–2 mm; pappi 3–4 mm | S. ericoides |
9. Involucres (4.5–)5–8 mm; ray florets (15–)20–35, laminae (8–)18–30 mm; disc corollas 2–2.5 mm, lobes 0.7–1.2; cypselae 2–2.5 mm; pappi4.5–6 mm | S. falcatum |
10. Phyllary apices flat | → 11 |
10. Phyllary apices involute or folded (green) | → 12 |
11. Stems usually ascending to erect, sometimes arching; disc corollas whitish to cream, lobes strongly reflexed, lanceolate, 0.9–1.7 mm(lengths 1/2 – 3/4 corollas) | S. lateriflorum |
11. Stems erect; disc florets yellow, lobes sometimes ± spreading, triangular, 0.4–1.2 mm (lengths to 1/2 corollas) | S. lanceolatum |
12. Plants colonial, long-rhizomatous or with short, branched caudices; ray florets (9–)11–17(–23), laminae (3.7–)5–5.5(–7.3); disc florets 5–16 (–28), corollas (2.3–)2.5–3.3(–3.7) | S. parviceps |
12. Plants cespitose with branched caudices, sometimes also long-rhizomatous; ray florets (10–)16–28(–38), laminae (4–)5.4–7.5(–11); disc florets (13–)17–39(–67), corollas (2.5–)3–4.1(–5.5) | S. pilosum |
13. Stems glabrous or glabrate distally, not hairy in lines in arrays | → 14 |
13. Stems hairy in lines (at least distally) | → 15 |
14. Leaves thick (fleshy); involucres narrowly turbinate; disc corolla lobes ± erect | S. tenuifolium |
14. Leaves thin; involucres cylindric to hemispheric; disc corolla lobes ± spreading | S. potosinum |
15. Basal and proximal leaf blades 15–50 mm wide, bases usually shallowly, sometimes deeply cordate to truncate or rounded (proximal sometimes attenuate), distal leaves ± shortly winged-petiolate or sessile; array branches stiffly ascending to erect | S. urophyllum |
15. Basal and proximal leaf blades 2–20(–25) mm wide, bases attenuate or cuneate, not cordate or truncate, distal leaves sessile; array branches ascending to ± divaricate | → 16 |
16. Phyllary apices involute or folded (green and spiny-looking, sometimes spreading, not foliaceous), acute to long-acuminate or cuspidate | → 17 |
16. Phyllary apices not involute or folded (sometimes spreading, outer phyllaries sometimes foliaceous), obtuse to acute or acuminate | → 20 |
17. Plants colonial or cespitose, rhizomatous or with short caudices; basal and proximal leaves sessile or subsessile; ray florets 7–17(–23), laminae (3–)3.8–5.5(–7.3) mm; disc florets 5–17(–28), corollas (2.2–)2.5–3.3(–3.7) mm | → 18 |
17. Plants cespitose, usually with caudices, sometimes rhizomatous; basal and proximal leaves usually petiolate, sometimes sessile (petioles ± winged, ± sheathing to clasping); ray florets (10–)16–34(–42), laminae (4–)5.4–15(–19) mm; disc florets (13–)17–75(–103), corollas (2.5–)3–4.6(–5.5) mm | → 19 |
18. Plants 20–50 cm; stems glabrate; leaf margins ciliate, apices acute; proximal cauline leaves linear-lanceolate (without axillary clusters); phyllary apices acute; ultramafic or diabasic soils, e of Appalachians | S. depauperatum |
18. Plants 30–100 cm, stems sparsely to densely pilosulous to hirtellous, proximally glabrescent; leaf margins strigoso-ciliate to scabrous, apices acute to acuminate, mucronulate; proximal leaves oblanceolate to lanceolate (often with axillary clusters of small leaves); phyllary apices acute to acuminate or cuspidate, sometimes aristate; sandy areas, rocky outcrops, fields, w of Appalachians | S. parviceps |
19. Leaves often with axillary clusters, margins ciliate, faces glabrous or ± hirsute (notably on abaxial midveins); array branches divaricate to ± ascending, often arched and secund, peduncle bracts 7–25+; ray laminae (4–)5.4–7.5(–11) × (0.4–)0.8–1.3(–1.7); disc florets (13–) 17–39(–67); easterndeciduous forests and adjacent prairies | S. pilosum |
19. Leaves without axillary clusters, margins scabrous, faces glabrous; array branches ascending, peduncle bracts 1–3; ray laminae 6.8–12 × 0.7–1.8; disc florets (30–)40–75(–103); foothills of Rocky Mountains, Colorado, New Mexico, Wyoming | S. porteri |
20. Cauline leaf blades lanceolate, linear, linear-lanceolate, or oblanceolate, bases ± clasping and/or ± auriculate, margins usually ± revolute (usually entire, sometime sparsely serrulate); heads 1–30+ in lax arrays | → 21 |
20. Cauline leaf blades ovate or elliptic to oblanceolate, lanceolate, or linear, bases attenuate or cuneate (if auriculate or clasping, blades not linear), margins usually flat, sometimes ± revolute (then ± serrate); heads (1–)10–100(–800+) in ± dense arrays | → 23 |
21. Rhizomes of season shallow, often thick, each producing a distal rosette in late season near parent plants; phyllaries often spreading to reflexed; hang-ing gardens, seeps, stream banks, w United States | S. welshii |
21. Rhizomes of season shallow or deep-seated, slender, not producing rosettes near parent plants; phyllaries usually appressed | → 22 |
22. Distal leaves (40–)50–150 × 2–6 mm; boreal fens, northern Rockies, boreal Canada | S. boreale |
22. Distal leaves 10–36 × 1–4 mm; hot springs on tufa deposits, Nahanni River, Northwest Territories | S. nahanniense |
23. Cauline leaf bases auriculate and clasping; arrays densely leafy (branch leaves often overtopping heads); involucres 6–12 mm | S. firmum |
23. Cauline leaf bases attenuate or cuneate (if proximal clasping, not auriculate and distal not clasping); arrays ± leafy (branch leaves usually not overtopping heads); involucres (2.5–)3–8 mm | → 24 |
24. Leaves firm; peduncles (0.5–)1–5 cm, bracts 5–16+, linear-oblong to subulate or subulate-foliaceous (1–2 mm) | S. dumosum |
24. Leaves usually pliable (± firm in S. eulae); peduncles 0 or 0.2–5 cm, and/or bracts 1–5, subulate, linear, or linear-lanceolate, if longer than 2 cm and/or bracts 5–15, linear-oblanceolate, lanceolate, or oblong-lanceolate and foliaceous | → 25 |
25. Plants cespitose, 5–50(–70) cm, short-rhizomatous; heads (10–)25–100 in paniculiform arrays with 1–10-headed, ascending branches; rocky or gravelly, silty shores, ne North America | S. tradescantii |
25. Plants colonial, (5–)30–150(–200) cm, long-rhizomatous (cespitose and short-rhizomatous in S. bracteolatum, w North America); heads (1–)10–400+ in racemiform to ± narrow, paniculiform, or open, paniculiform arrays with ± ascending to divaricate or spreading branches | → 26 |
26. Cauline leaf margins usually entire; arrays racemiform to ± narrow, paniculiform, branches ascending; cypselae not compressed; w North America | → 27 |
26. Cauline leaf margins ± serrate or entire; arrays open, paniculiform, branches ± ascending to divaricate or spreading, secund or not; cypselae ± compressed; e North America | → 28 |
27. Plants cespitose, 40–100 cm, short-rhizomatous; phyllaries subequal, acute to obtuse, often spreading; ray florets 20–40; disc florets 35–60+; 500–3100 m, sw Canada to California | S. bracteolatum |
27. Plants colonial, 30–60 cm, long-rhizomatous; phyllaries unequal, obtuse, appressed; ray florets 14–25; disc florets 20–35; 0–500 m, Oregon, Washington | S. hallii |
28. Disc corolla lobes spreading to strongly reflexed (lengths mostly 1/2 – 3/4 corollas); stems ascending to erect | → 29 |
28. Disc corolla lobes usually erect (lengths to 1/2 corollas); stems erect | → 30 |
29. Plants cespitose, with short, branched caudices or short-rhizomatous; abaxial leaf faces glabrous, midveins ± densely pilose (rarely glabrate); ray florets 8–15(–23); disc corollas white to cream turning pink to purplish, lobes strongly reflexed (lengths 1/2 – 3/4 corollas); wet to mesic, deciduous or mixed woods, clear-ings, banks,roadsides | S. lateriflorum |
29. Plants colonial, long-rhizomatous; abaxial leaf faces and midveins usually sparsely to densely strigose or strigillose, sometimes glabrous (var. glabratum); ray florets (10–)15–26; disc corollas cream to light yellow turning purple to brown, lobes spreading (lengths ca. 1/2 corollas); alluvial woods and shores | S. ontarionis |
30. Leaf margins flat, sparsely serrate or entire; proximal leaves sessile or subsessile (± decurrent), only slightly reduced distally; array branches ascending, peduncle bracts 1–3(–5), linear-oblanceolate to -lanceolate,foliaceous (not grading into phyllaries) | S. lanceolatum |
30. Leaf margins ± revolute, serrate or entire; proximal leaves (winged-) petiolate or subpetiolate, progressively reduced distally; array branches usually widely spreading or horizontal, sometimes ascending, branch leaves small, peduncle bracts 5–15+, linear-elliptic to linear or acicular, sometimes foliaceous, grading into phyllaries | → 31 |
31. Arrays diffuse, ± pyramidal, branches lax, horizontal or arching (subtended by patent to reflexed branch leaves), bracts linear; involucres cylindric, (2.5–)3.5–4.5(–5.5) mm; phyllaries appressed, green zones oblanceolate to linear-oblanceolate; ray florets (12–)16–20, laminae 5–8 × 0.5–1.2 mm; disc corollas pale yellow or cream, (2.5–)3–4.5 mm, lobes 0.5–1 mm; e North America | S. racemosum |
31. Arrays open, branches divaricate or nearly horizontal to ascending, bracts ± foliaceous; involucres hemispheric, (4–)5–6.5 mm; phyllaries slightly spreading, green zones lanceolate (prominent); ray florets (20–)27–36, laminae 8–11 × 1–1.5 mm; disc corollas yellow, (4.1–)4.5–5.8 mm, lobes 1.1–1.3 mm; Texas | S. eulae |
32. Stems moderatly to densely hairy | → 33 |
32. Stems glabrous (usually distally hairy in lines, at least in arrays) or sparsely hairy | → 63 |
33. Phyllaries ± stipitate-glandular (at least apically) | → 34 |
33. Phyllaries eglandular | → 45 |
34. Stems scandent-climbing to erect; distal leaves adnate to stems for 1/2 + their lengths, viscid | S. adnatum |
34. Stems decumbent, ascending, or erect, not scandent-climbing; distal leaves not adnate to stems, not viscid | → 35 |
35. Proximal and distal leaf bases auriculate- or cordate-clasping, distal sometimes cuneate | → 36 |
35. Proximal leaf bases rounded, cuneate, or ± clasping, not auriculate, distal cuneate to ± clasping | → 40 |
36. Distal leaf bases cuneate; phyllaries sparsely scabrous | S. grandiflorum |
36. Distal leaf bases auriculate- or cordate-clasping; phyllaries glabrous, ± strigillose, or cinereous-puberulent | → 37 |
37. Phyllaries subequal, outer foliaceous, margins stipitate-glandular, faces glabrous, densely glandular; ray florets (40–)50–75(–100);disc florets 50–100 | S. novae-angliae |
37. Phyllaries unequal, not foliaceous (green zones diamond-shaped or lance-spatulate in distal 1/2), margins ciliate, sometimes also stipitate-glandular apically, faces ± strigillose or cinereous-puberulent, ± glandular; ray florets 9–24+; disc florets 15–50 | → 38 |
38. Plants colonial, short- to long-rhizomatous; leaf margins revolute, sometimes ± undulate; distal leaf bases ± auriculate-clasping to subclasping; ray laminae 14–24 × 1.5–3.5 mm | S. georgianum |
38. Plants cespitose; leaf margins flat, not undulate; distal leaf bases strongly cordate-clasping to auriculate-amplexicaul; ray laminae 10–18(–20) × 1–3 mm | → 39 |
39. Leaves thick, firm; phyllaries strongly unequal, appressed to squarrose; disc corollas yellow to white, turning purplish, lobes 0.5–1 mm | S. patens |
39. Leaves thin, pliable (almost membranous); phyllaries unequal, appressed; disc corollas white with purple lobes, lobes 1–1.5 mm | S. phlogifolium |
40. Stems ± villous, more densely so distally | → 41 |
40. Stems ± strigose, hispid, hirsute, or hirtellous, sometimes proximally glabrous | → 42 |
41. Plants 1.5–15 cm; stems decumbent to ascending, eglandular; leaf faces sparsely villous, eglandular; cauline leaf blades lanceolate to oblong-lanceolate or oblong, proximal 30–50 × 3–10 mm, distal 13–19 × 2–4 mm, faces sparsely woolly, sometimes sparsely stipitate-glandular; heads borne singly; peduncles densely villous to lanate distally, eglandular; involucres 9–12.5 mm; outer phyllaries ± foliaceous, woolly to densely villous, ± minutely stipitate-glandular (apically) | S. pygmaeum |
41. Plants 5–30 cm; stems erect, stipitate-glandular; leaf faces glabrate to sparsely strigose, distal ± stipitate-glandular; cauline leaf blades linear to linear-lanceolate, proximal 20–70 × 1–4 mm, distal 10–30 × 1–2.5 mm, faces glabrous or sparsely villous, stipitate-glandular; heads 1–3(–6), borne singly or in open, corymbo-paniculiform arrays; peduncles ± densely short-villous, ± glandular; involucres 7–10 mm; outer phyllaries foliaceous (at least distally), ± denselyvillous, stipitate-glandular | S. yukonense |
42. Stems, leaves, and peduncles eglandular, outer phyllaries eglandular, inner distally stipitate-glandular; heads (5–)30–150+; cypselae densely sericeous | S. ×amethystinum |
42. Stems, leaves (usually at least distal), peduncles, and phyllaries ± stipitate-glandular; heads 1–30(–70); cypselae usually sparsely to moderately strigose or strigillose, sometimes sparsely sericeous | → 43 |
43. Plants 10–80(–100) cm; leaves thin, apices obtuse; outer phyllaries often broadly foliaceous, abaxial faces moderately hairy; Central Lowlands | S. oblongifolium |
43. Plants 6–40 cm; leaves thick (firm), apices acute, ± mucronate; outer phyllaries not foliaceous, or only apices foliaceous, abaxial faces glabrous or glabrate | → 44 |
44. Plants rhizomatous; stems ascending to erect; phyllaries glabrate; ray florets 15–31; disc florets 25–40; cypsela ribs 3–4, shallow; cordilleran | S. campestre |
44. Plants with thick, woody caudices; stems decumbent to ascending, sometimes erect; phyllaries glabrous; ray florets 10–20; disc florets (7–)10–30; cypsela ribs 7–10; High Plains | S. fendleri |
45. Basal and proximal leaves petiolate or winged-petiolate, blades ovate to lanceolate, bases usually ± cordate or rounded, sometimes truncate or attenuate | → 46 |
45. Basal leaves petiolate or sessile, blades spatulate or oblanceolate to elliptic-lanceolate, bases (not cordate) cuneate or attenuate, proximal petiolate or sessile, blades ovate or obovate to oblong, lanceolate, or oblanceolate, bases cuneate or attenuate, sometimes auriculate- or cordate-clasping (and sessile) or subclasping. | → 49 |
46. Cauline leaves winged-petiolate, wings wider distally and leaves ± sessile, the wingsabruptly widening at the strongly auriculate-clasping petiolar bases | S. undulatum |
46. Cauline leaves ± narrowly winged-petiolate, the wings not widening at the ± clasping petiolar bases | → 47 |
47. Basal and proximal cauline leaves ± cordate, rounded, or attenuate; phyllary faces glabrous; cypselae 1.8–2 mm, glabrate to sparsely strigose | S. oolentangiense |
47. Basal and proximal cauline leaves ± deeply cordate; phyllary faces ± hairy; cypselae (1–)2.5–3.7 mm, glabrous | → 48 |
48. Stems proximally usually ± densely hirtellous, sometimes glabrescent, distally hirsute; phyllary apices reflexed to squarrose, long-acuminate, ± foliaceous, not involute, apiculate, faces strigoso-hirtellous; ray corollas lavender-blue to purple | S. anomalum |
48. Stems proximally glabrous, distally ± densely hirtellous; phyllary apices ± appressed, not foliaceous, acute to acuminate, often involute, mucronulate, abaxial faces strigillose-hirsutulous; ray corollas blue | S. shortii |
49. Stems densely puberulent to lanate, especially distally; leaves densely lanate-puberulent | → 50 |
49. Stems strigose, hirsute, hispid, woolly-pilose, canescent, or cinereous-puberulent; leaves silvery-silky, strigose, hispid, pilose, or scabrous | → 51 |
50. Plants 30–60 cm; leaves oblanceolate, cauline bases slightly clasping; peduncle bracts 0–3; nc Wyoming | S. molle |
50. Plants 40–150 cm; leaves obovate to elliptic, cauline bases often clasping and auriculate; peduncle bracts 1–8, foliaceous; Palouse region, nw Idaho, se Washington | S. jessicae |
51. Leaf margins usually ± serrate or crenate-serrate, sometimes entire | → 52 |
51. Leaf margins entire or ± serrulate | → 53 |
52. Plants cespitose (stems 1–5+), (7–)100–250+ cm, with short, thick rhizomes or stout caudices; cauline leaves widely winged-petiolate or sessile (distal), bases ± strongly auriculate-clasping; phyllaries subequal, green zones linear-lanceolate to linear, outer sometimes ± foliaceous; ray florets 20–50(–60), laminae (7–)12–18(–21) × (0.9–) 1.4–1.8 mm | S. puniceum |
52. Plants colonial (stems 1), 15–40(–60) cm, with long thin rhizomes; cauline leaves ± winged-petiolate to subsessile, bases usually attenuate; phyllaries slightly unequal, green zones rhombic-lanceolate; ray florets 18–32, laminae 6–9 × 0.8–1.4 mm; ultramafic outcrops, North Carolina | S. rhiannon |
53. Stems erect to scandent-climbing, branched from mid to distal nodes; leaves thick, firm, ± succulent, patent to reflexed; heads borne singly, overall in diffusely paniculiform arrays | S. walteri |
53. Stems ascending to erect, not scandent, usually simple; leaves usually thin, sometimes thick, firm, not succulent, not reflexed; heads in racemiform to paniculiform arrays | → 54 |
54. Proximal cauline leaf bases auriculate- or cordate-clasping, distal clasping or subclasping | → 55 |
54. Proximal cauline leaf bases tapering, rounded or subclasping (not auriculate), distal cuneate | → 56 |
55. Proximal cauline leaf bases not constricted proximally; distal leaf blades lanceolate or oblanceolate to oblong-lanceolate, bases cuneate to rounded, subclasping, apices acute or acuminate, subspinulose; involucres 6–7.6 mm; cypselae sparsely strigillose to glabrate | S. fontinale |
55. Proximal cauline leaf bases broadened proximal to constriction; distal leaf blades narrowly to broadly ovate, bases strongly cordate-clasping to auriculate-amplexicaul, apices usually acute, sometimes obtuse, mucronate to white-spinulose; involucres 5.5–12 mm; cypselae seri ceous or strigillose | S. patens |
56. Distal leaf apices not mucronate or spinulose; ray corollas violet | → 57 |
56. Distal leaf apices white-spinulose or mucronate; ray corollas blue, pink, lavender, rose-purple, or violet | → 58 |
57. Plants colonial, 20–60 cm, long-rhizomatous; cauline leaves oblong to narrowly obovate, distal 30–70 × 4–10 mm, glabrous or strigose; arrays paniculiform | S. ascendens |
57. Plants cespitose, (30–)40–100(–120) cm, short rhizomatous; cauline leaves linear to narrowly oblong, distal 15–80 × 2–8 mm, ± denselystrigose; arrays narrow, paniculiform | S. defoliatum |
58. Leaf faces ± strigose; disc corollas yellow becoming brown | → 59 |
58. Leaf faces long-silvery-silky or pilose to scabrous; disc corollas pink becoming purple | → 60 |
59. Plants colonial or cespitose, 10–80 cm, rhizomatous or with woody, cormoid caudices; disc corollas 2–2.5 mm, lobes 0.7–1.2 mm; cypselae 2–2.5 mm, densely strigose, pappi whitish | S. falcatum |
59. Plants cespitose, 30–120 cm, caudices thick, woody; disc corollas 3–4 mm, lobes 0.5–0.7 mm; cypselae 1.5–2 mm, densely sericeous, pappi tan to tawny, sometimes rose- or violet-tinged | S. ×amethystinum |
60. Stems simple; distal leaves 8–15 × 1.8–5 mm; arrays narrow (wand-shaped), paniculiform, sometimes racemiform; outer phyllaries not foliaceous; ray florets 7–12; disc florets 9–21; cypselae densely strigose | → 61 |
60. Stems ± branched; distal leaves 10–30 × 4–8 mm; arrays open, paniculiform; outer phyllaries ± foliaceous (at least distally); ray florets 13–36; disc florets 15–48; cypselae glabrous | → 62 |
61. Leaf faces glabrous or densely canescent distally; involucres 5–7 mm; phyllaries appressed | S. concolor |
61. Leaf faces sparsely to moderately finely woolly-pilose, denser distally; involucres 7–9 mm; phyllaries spreading to reflexed | S. plumosum |
62. Leaf margins piloso-scabrous, faces glabrous or glabrate to ± strigose distally, proximal apices cuspidate mucronate; distal leaf blades oblong-lanceolate, apices white-spinulose; peduncles glabrous or sparsely strigose; phyllaries subequal, outer foliaceous, glabrous or sparsely short-pilose | S. pratense |
62. Leaf margins piloso-silky, faces glabrous proximally, densely silky distally, proximal apices mucronulate; distal leaf blades lanceolate, apices mucronate; peduncles densely sericeous-strigose; phyllaries usually unequal, sometimes subequal, outer with expanded, ± foliaceous distal 1/2 – 2/3, densely long-silky | S. sericeum |
63. Basal leaves persistent to flowering or petiole bases marcescent, long-petiolate, linear to linear-lanceolate; cauline leaves linear, clasping to subclasping; pine flatwoods, acidbogs, Alabama, Florida; (subg. Chapmaniani) | S. chapmanii |
63. Basal leaves usually withering by flowering (petiole bases not marcescent, if leaves persistent or present as secondary rosettes, not linear and long-petiolate); cauline leaves not both linear and clasping | → 64 |
64. Stems glabrous, without lines of hairs distally; cauline leaves fleshy, margins entire, faces glabrous; involucres narrowly turbinate | S. tenuifolium |
64. Stems glabrous and with lines of hairs distally, or sparsely hairy; cauline leaves thin or thick, not fleshy, margins entire or ± serrate, faces glabrous or ± hairy; involucres cylindric to campanulate or hemispheric | → 65 |
65. Basal and proximal cauline leaves petiolate, blades ± ovate, bases ± deeply cordate or rounded, proximal sometimes truncate, cuneate, or attenuate | → 66 |
65. Basal and proximal cauline leaves petiolate or sessile, blades ovate to lanceolate or linear, bases usually cuneate or attenuate, sometimes rounded (if cordate-clasping, then usually sessile) | → 72 |
66. Basal leaf bases shallowly cordate or rounded to attenuate, proximal cauline bases rounded to attenuate | → 67 |
66. Basal leaf bases usually ± deeply cordate, sometimes rounded or abruptly attenuate, proximal cauline bases ± cordate, rounded, or truncate, sometimes cuneate | → 69 |
67. Leaf faces scabrous, adaxially strongly strigose, abaxially strigose topiloso-strigose or hirsute | S. oolentangiense |
67. Leaf faces glabrous | → 68 |
68. Plants cespitose (glaucous); proximal and distal leaf margins entire (at most crenulate), distal bases auriculate and ± clasping to rounded, margins flat; phyllaries appressed (green zones diamond-shaped to lanceolate) | S. laeve |
68. Plants colonial (not glaucous); proximal leaf margins serrate, distal bases cuneate and not clasping or slightly rounded and ± clasping, margins (serrulate or entire) revolute; phyllaries spreading to squarrose (outer foliaceous, inner green zones basally truncate or lanceolate) | S. retroflexum |
69. Plants colonial and cespitose, usually rhizomatous, sometimes with branched caudices; leaf margins usually sharply or coarsely serrate, sometimes crenate-serrate or serrulate | → 70 |
69. Plants cespitose, with short rhizomes or caudices; leaf margins ± shallowly serrate, serrulate, crenate-serrate, or entire | → 71 |
70. Basal and proximal leaf bases usually ± deeply cordate, sometimes rounded, distal blades ovate to lanceolate, bases cordate, rounded, attenuate, or cuneate, adaxial faces usually glabrous or sparsely to densely strigose, sometimes ± scabrous, abaxial glabrous or ± strigoso-pilose, often ± pilose on veins; heads (5–)20–300+ in densely paniculiform arrays, branches divaricate to ascending; involucres cylindro-campanulate to cylindric, (3–)4.5–5(–6) mm; phyllary green zones apical, lanceolate to diamond-shaped (often red-tipped); ray laminae (5–)6–8(–10) × 1.4–1.8 mm; e deciduous forests | S. cordifolium |
70. Basal leaf bases shallowly cordate to rounded, proximal subcordate or cuneate; distal blades lance-ovate to linear, bases cuneate; adaxial leaf faces glabrous, glabrate, or scabrellous, abaxial glabrate to sparsely hirsute, midveins usually densely hirsute, sometimes glabrous; heads (6–)13–50(–100+) in open, paniculiform arrays, branches ascending; involucres campanulate, (4–)5–6.5 mm; phyllary green zones lanceolate to linear along midnerves; ray laminae(8.3–)10–15 × 1–2.3 mm; boreal forests | S. ciliolatum |
71. Cauline leaves petiolate, bases usually cordate to subcordate proximal to arrays, margins entire or serrulate; array branches widely spreading, divaricate to arching; phyllary green zones lanceolate to diamond-shaped, faces strigilloso-hirsute; ray corollas usually blue, laminae (10–)11–16 × 1.3–3.1 mm; disc florets 16–23(–28+), corollas 4.6–7 mm; pappi reddish brown, tawny, or rose-tinged | S. shortii |
71. Cauline leaves winged-petiolate, becoming broadly so or sessile distally, bases rounded or attenuate below arrays, margins serrate to crenate-serrate, entire distally; array branches ascending to divaricate; phyllary green zones lanceolate to linear-lanceolate, faces glabrous; ray corollas usually blue to purple, laminae (5–)7–10(–12) × 1–1.8 mm; disc florets (10–)13–15(–22), corollas 3.5–4.5(–5) mm; pappi cream to rose-tinged | S. drummondii |
72. Proximal cauline leaves sessile, blade bases rounded and subclasping, or cordate-clasping | → 73 |
72. Proximal cauline leaves petiolate and blade bases rounded, attenuate, or cuneate, or sub-petiolate or sessile and blade bases usually attenuate, cuneate, or ± auriculate-clasping | → 76 |
73. Stems scandent-climbing to erect, divaricately branched from mid to distal nodes; leaves thick, ± succulent, margins ciliate; heads in diffuse, paniculiform arrays; phyllary faces sparsely strigillose (cuticles often thick, shiny); disc corollas yellow | S. walteri |
73. Stems erect, ascending, or arching, not scandent, simple or sparsely branched; leaves not thick, not succulent, margins piloso-silky or -scabrous; heads in narrow, open, paniculiform arrays; phyllaries ± silky, woolly-strigose, sparsely short-strigose, or glabrous; disc corollas pink | → 74 |
74. Stems sparsely branched; distal leaves 15–25 × 4–6 mm; arrays open, paniculiform; ray florets 13–36; disc florets 15–48; cypselae glabrous | S. pratense |
74. Stems simple; distal leaves 8–15 × 1.8–5 mm; arrays narrow, paniculiform (wand-shaped); cypselae densely strigose | → 75 |
75. Leaf faces glabrous or densely canescent distally; involucres 5–7 mm; phyllaries appressed | S. concolor |
75. Leaf faces sparsely to moderately finely woolly-pilose, denser distally; involucres 7–9 mm; phyllaries spreading to reflexed | S. plumosum |
76. Proximal cauline leaves petiolate to subpetiolate, petioles ± narrowly winged, blades ± ovate to lanceolate, bases rounded to attenuate (sometimes auriculate-clasping distally, then sessile) | → 77 |
76. Proximal cauline leaves sessile or subpetiolate, petioles widely winged, blades ovate, elliptic, oblanceolate, or lanceolate to linear, bases attenuate to cuneate, often auriculate-clasping | → 79 |
77. Leaf faces scabrous, adaxially strongly strigose, abaxially strigose to piloso-strigose or hirsute | S. oolentangiense |
77. Leaf faces glabrous | → 78 |
78. Plants cespitose (glaucous); proximal and distal leaf margins usually entire, sometimes crenulate, distal bases auriculate and ± clasping to rounded, margins flat; phyllaries appressed (green zones diamond-shaped to lanceolate) | S. laeve |
78. Plants colonial (not glaucous); proximal leaf margins serrate, distal bases cuneate, not clasping, to slightly rounded and ± clasping, margins serrulate or entire, revolute; phyllaries spreading to squarrose (outer foliaceous, inner green zones basally truncate or lanceolate) | S. retroflexum |
79. Proximal and distal cauline leaves ovate, obovate, elliptic, oblanceolate, or lanceolate, distal sometimes lanceolate-linear or linear | → 80 |
79. Proximal and distal cauline leaves narrowly lanceolate or oblanceolate or elliptic, linear-oblanceolate or -lanceolate, to linear or subulate | → 93 |
80. Cauline leaf bases usually not or little clasping, sometimes slightly rounded or auriculate | → 81 |
80. Cauline leaf bases (at least some) usually cuneate, sometimes attenuate, usually ± clasping, often ± auriculate or rounded, margins serrate (proximal), crenate-serrate, or entire | → 86 |
81. Plants short-rhizomatous; arrays racemiform to narrow, paniculiform, branches ascending (to 10 cm); ray corollas pink | S. bracteolatum |
81. Plants long-rhizomatous; arrays paniculiform to corymbiform, usually open, sometimes racemiform (then open or elongate); ray corollas usually violet or purple to blue, sometimes pale, sometimes lavender or rose-purple | → 82 |
82. Phyllary green zones (outer) obovate to oblanceolate or elliptic to linear; ray laminae 9–16 × 1–2 mm; w North America | → 83 |
82. Phyllary green zones (outer) oblanceolate to linear-lanceolate or lance-rhombic; ray laminae 3–11 × 0.5–1.7 mm | → 84 |
83. Outer phyllaries obtuse (usually shorter than inner); cypselae 3.5–4.5mm; grasslands and marshy areas; Pacific Coast | S. chilense |
83. Outer phyllaries usually acute (shorter than or equal to inner); cypselae 2–3.5 mm; disturbed habitats | S. subspicatum |
84. Leaves thin, margins flat; peduncle bracts 5–12+; phyllaries linear-lanceolate (outer), subequal to unequal, outer often foliaceous | S. lanceolatum |
84. Leaves firm, margins often recurved; peduncle bracts 1–3(–5); phyllaries oblong-lanceolate (outer), ± unequal, outer sometimes foliaceous | → 85 |
85. Cauline leaves sharply reduced on array branches, adaxial faces not waxy, abaxial with indistinct, elongate areoles (axillary clusters absent); peduncle bracts reduced, grading into phyllaries; disc corollas yellow turning reddish; cypselae 2–2.6 mm; peninsular Florida, North Carolina, South Carolina | S. simmondsii |
85. Cauline leaves progressively reduced distally, adaxial faces waxy, abaxial with well-marked, isodiametric areoles (axillary clusters often present); peduncle bracts foliaceous, distal closely subtending heads, not grading into phyllaries; disc corollas cream to pale yellow turning pinkish; cypselae 1.5–2 mm; e North America | S. praealtum |
86. Cauline leaf bases attenuate, cuneate, or rounded, sometimes ± clasping, not auriculate | → 87 |
86. Cauline leaf bases cuneate or attenuate, ± strongly auriculate and clasping | → 88 |
87. Cauline leaves firm, margins serrate to serrulate, distal entire; array branches strongly ascending; peduncle bracts 3–5, linear; outer phyllaries distally foliaceous, inner green zones lanceolate to linear; rays pink or lavender; disc florets 25–35+; Atlantic coastal plain | S. elliottii |
87. Cauline leaves thin, margins usually entire, sometimes serrate; array branches ascending; peduncle bracts 0–3, lanceolate; outer phyllaries foliaceous, green zones elliptic to lanceolate; rays violet to purple; discflorets 50–150; w North America | S. foliaceum |
88. Stems usually flexuous; petiole and leaf bases strongly dilated (blades sometimes panduriform); leaf margins serrate; arrays corymbo-paniculiform; e North America | S. prenanthoides |
88. Stems straight; petiole and leaf bases not dilated; leaf margins usually serrate or crenate-serrate, sometimes entire; arrays paniculiform | → 89 |
89. Leaf faces scabrous or glabrate, sometimes abaxially pilose on midveins | → 90 |
89. Leaf faces glabrous or puberulent, sometimes abaxially villosulous on midveins | → 91 |
90. Plants cespitose, with short, thick rhizomes or caudices; leaf faces adaxially glabrate to scabrous, abaxially pilose on midveins; phyllary apices long-acuminate to caudate; e NorthAmerica | S. puniceum |
90. Plants colonial, long-rhizomatous; leaf faces scabrous; phyllary apices acute; California | S. greatae |
91. Peduncles cinereous; involucres 10–20 mm; disc florets 60–150+; w North America | S. cusickii |
91. Peduncles glabrous or ± pilose; involucres 6–12 mm; disc florets 28–68; e North America | → 92 |
92. Leaf margins crenulate or entire, revolute; array branches ascending, densely leafy, branch leaves overtopping heads; ray corollas usually blue or pale lavender; wet habitats, easternprairies to Appalachians | S. firmum |
92. Leaf margins serrate or entire, flat; array branches ± divaricate to ascending, remotely small-leaved; ray corollas usually blue-violet or purple, rarely pink; stream andsea shores, Atlantic coast | S. novibelgii |
93. Involucres cylindro-campanulate or turbinate | → 94 |
93. Involucres campanulate | → 99 |
94. Phyllary apices involute; cedar glades | S. priceae |
94. Phyllary apices not involute | → 95 |
95. Heads 10–800+ in open arrays; stems erect (± brittle); leaves thick, firm; rhizomes or caudices thick, woody; temperate e North America | → 96 |
95. Heads 1–30 in often lax, open arrays; stems ascending to erect (not brittle); leaves thin, sometimes stiff; rhizomes usually slender, sometimes woody; cordilleran and boreal North America | → 97 |
96. Distal leaves 2–45 × 0.5–4 mm, often with axillary clusters; involucres cylindro-campanulate, (3–)4.5–6.3 mm; phyllaries in 4–6 series; ray corollas pale blue, pink, or lavender (white), laminae (4–)5–7(–8) mm | S. dumosum |
96. Distal leaves (10–)15–100 × 1–5 mm, without axillary clusters; involucres turbinate to cylindro-campanulate, 7–12 mm; phyllaries in 6–9 series; raycorollas light blue to purple, laminae 12–20 mm | S. turbinellum |
97. Rhizomes of season shallow, often thick, each producing a distal rosette in late season near parent plants; phyllaries often spreading to reflexed; hang-ing gardens, seeps, stream banks, w United States | S. welshii |
97. Rhizomes of season shallow- or deep-seated, slender, not producing rosettes near parent plants; phyllaries usually appressed | → 98 |
98. Distal leaves (40–)50–150 × 2–6 mm; boreal fens, northern Rockies,boreal Canada | S. boreale |
98. Distal leaves 10–36 × 1–4 mm; hot springs on tufa deposits, NahanniRiver, Northwest Territories | S. nahanniense |
99. Plants cespitose, short-rhizomatous; heads (10–100+) in ± dense, racemiform to narrow, paniculiform arrays; rays pink; w North America | S. bracteolatum |
99. Plants mostly colonial, sometimes ± cespitose, long-rhizomatous; heads usually in open, paniculiform arrays (if racemiform or narrow, paniculiform then heads 10–20+ and arrays open, elongate, e North America); rays violet or purple to pale blue-violet, pale purple, or lavender | → 100 |
100. Cauline leaf bases cuneate, usually ± clasping, often ± auriculate or rounded, margins often serrate (proximal) or crenate-serrate, distal sometimes entire;Atlantic seaboard and adjacent areas | S. novibelgii |
100. Cauline leaf bases usually not or little clasping, sometimes slightly rounded or auriculate, margins serrulate or entire | → 101 |
101. Basal leaves persistent to flowering; cypselae hairy; w North America | → 102 |
101. Basal leaves withering by flowering; cypselae glabrous or ± sparsely strigillose | → 103 |
102. Cauline leaves elliptic to oblanceolate; arrays much branched; bracts2–10; cypselae 3–3.5 mm | S. hendersonii |
102. Cauline leaves narrowly elliptic to linear; arrays usually few-branched;bracts 0–3+; cypselae 2.5–3.5 mm | S. spathulatum |
103. Adaxial leaf faces ± waxy, abaxial with marked, isodiametric areoles; disc corollas cream to pale yellow | S. praealtum |
103. Adaxial leaf faces not waxy, abaxial with indistinct, irregular areoles; disc corollas yellow | → 104 |
104. Leaves pliable, margins flat | → 105 |
104. Leaves firm or stiff, margins often ± revolute | → 106 |
105. Arrays paniculiform (leafy), branches ascending; peduncle bracts 1–3(–5); phyllaries usually ± subequal, sometimes unequal, bases 1 /4 – 1/2 indurate (outer often foliaceous); ray laminae 3–10(–14) × 0.5–1.3 mm; disc corollas 2.8–5.8 mm widespread | S. lanceolatum |
105. Arrays paniculiform, branches spreading; peduncle bracts 5–15; phyllaries unequal, bases 1/2 + indurate (outer not foliaceous); ray laminae 10–18 × 1–2 mm; disc corollas 5–7 mm | S. lentum |
106. Proximal cauline leaves 45–70+ mm; arrays racemiform to open, ± lax, paniculiform, branches ascending to spreading, often arched (each usually with 10+ heads); peduncle bracts 7–12+; phyllaries in 5–6 series, strongly unequal, outer sel-dom foliaceous; se United States | S. simmondsii |
106. Proximal cauline leaves 90–200 mm; arrays (elongate) loose, racemiform, or narrow, paniculiform, branches ascending (each usually with 1–3 heads); peduncle bracts 1–5; phyllaries in 2–4 series, subequal to ± unequal, outer often foliceous or foliaceous distally; ne North America. | → 107 |
107. Stems straight; leaves arcuate, proximal narrowly winged-petiolate, not clasping; heads usually 1 per elongate branch or peduncle; phyllaries ± unequal; New Brunswick,e Quebec, Maine | S. anticostense |
107. Stems ± flexuous; leaves not arcuate, proximal sessile or subpetiolate, ± clasping; heads 1–3 per branch; phyllaries subequal; Manitoba, Ontario, w Quebec, Michigan, Minnesota, Wisconsin | S. robynsianum |
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