Asteraceae (tribe Heliantheae) subtribe Ecliptinae
(synonym of Asteraceae tribe Heliantheae subtribe Ecliptinae)
Zinnia
zinnia
prostrate or erect.
usually cauline, sometimes mostly basal, or basal and cauline; opposite, alternate, or both;
petiolate or sessile;
blades cordate, deltate, elliptic, lanceolate, linear, rhombic, orbiculate, or ovate (and intermediate shapes), often 1(–2+)-palmately or -pinnately lobed, ultimate margins entire or toothed, faces glabrous or hairy (often hispid or scabrous), often gland-dotted or stipitate-glandular.
cauline; opposite or subopposite;
sessile [petiolate];
blades (1-, 3-, or 5-nerved from bases) acerose, elliptic, lance-linear, lanceolate, linear, oblong, or ovate, bases rounded to cuneate, margins entire, faces hairy (often scabrous or scabrellous), usually gland-dotted.
cylindric, or campanulate to hemispheric or broader, or rotate.
campanulate, cylindric, to hemispheric or broader, 5–25 mm diam.
convex, conic, or flat, paleate (paleae usually falling, oblong to linear, herbaceous to chartaceous or scarious, usually conduplicate).
conic, paleate (paleae yellowish, often reddish to purplish distally, chartaceous to scarious, conduplicate, apices rounded to acute, sometimes fimbriate).
usually (1–)3–40+, sometimes 0, usually pistillate and fertile, sometimes styliferous and sterile, or neuter;
corollas usually yellow to orange, sometimes pink to purple, red, brown, or white (sometimes sessile, persistent, and becoming papery, e.g., in Heliopsis, Sanvitalia, and Zinnia).
usually 5–21 (more in “double” cultivars, sometimes 0 in Z. anomala), pistillate, fertile;
corollas yellow, orange, red, maroon, purple, or white (laminae persistent, sessile or nearly so, becoming papery, sometimes much reduced).
4–200+, bisexual and fertile, or functionally staminate;
corollas usually yellow to orange, sometimes brown, greenish, maroon, pink, purple, or red, rarely white or whitish, tubes shorter to longer than campanulate, cylindric, or funnelform throats, lobes (4–)5, deltate to lanceolate (usually equal);
anther thecae usually dark (collars not continuous around filaments);
stigmatic papillae usually continuous, sometimes none, rarely in 2 lines.
20–150+, bisexual, fertile;
corollas usually yellow to reddish, sometimes purple-tinged, tubes much shorter than cylindric throats, lobes 5, lance-ovate (usually unequal, usually villous or velutinous adaxially).
persistent or falling, usually 8–40+ in 2–4+ series, usually distinct, usually lanceolate, linear, orbiculate, or ovate, subequal or unequal (outer usually shorter, rarely longer, than inner).
persistent, 12–30+ in 3–4+ series (orbiculate to obovate or oblong, unequal, often colored or dark-banded distally, outer shorter).
0.
usually radiate, sometimes discoid, borne singly or in cymiform, corymbiform, paniculiform, racemiform, or spiciform arrays.
usually radiate (rarely ± discoid in Z. anomala), borne singly.
obpyramidal or prismatic (3–4-angled), or terete to ovoid, or strongly compressed or flattened and ± orbiculate to obovate or cuneate (lengths seldom more than 2 times diams.), sometimes ribbed, sometimes winged, glabrous or hairy;
pappi usually persistent, sometimes fragile or readily falling, usually of scales, sometimes of bristles or bristlelike awns or coroniform, rarely of awns or 0.
3-angled (ray) or flattened (disc; not winged);
pappi 0, or persistent, of 1–3(–4) awns or toothlike scales.
= 12 (11, 10).
Asteraceae (tribe Heliantheae) subtribe Ecliptinae
Zinnia
Genera 75, species 600 (31 genera, 124 species, including 4 hybrids, in the flora).
The circumscription of Ecliptinae adopted by H. Robinson (1981) and followed here differs from the treatment by P. O. Karis and O. Ryding (1994), who placed Eclipta as unassigned to a subtribe and placed Echinacea in Rudbeckiinae, Acmella, Heliopsis, Sanvitalia, and Zinnia in Zinniinae, Berlandiera, Chrysogonum, Engelmannia, Lindheimera, and Silphium in Engelmanniinae, and Balsamorhiza (including Agnorhiza), Borrichia, Calyptocarpus, Encelia, Enceliopsis, Flourensia, Geraea, Helianthella, Jefea, Lasianthaea, Melanthera, Pascalia, Phoebanthus, Sphagneticola, Synedrella, Verbesina, Wedelia, and Wyethia (including Scabrethia) in Verbesininae. Based on studies of chloroplast DNA sequences, J. L. Panero (2005) placed Encelia, Enceliopsis, Flourensia, Geraea, and Helianthella together in Enceliinae and Acmella in Spilanthinae, indicating a sister relationship between Spilanthinae and traditionally circumscribed Zinniinae.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Species ca. 17 (5 in the flora).
A. M. Torres (1963) recognized subg. Diplothrix, comprising six species, including the three perennial species treated here, and subg. Zinnia, comprising 11 species, mostly annuals. This division is reflected in the first couplet of the key.
Zinnia angustifolia Kunth (= Z. linearis Bentham), native to northern and western Mexico, is commonly grown as an ornamental in the United States and has been reported from Utah (S. L. Welsh et al. 1993); the record was likely from a cultivated source. The species also persists in gardens in California; it is not known outside of cultivation. It can be distinguished from other zinnias by the combination of annual habit, plants to 50 cm, leaf blades linear to narrowly elliptic (mostly 2–7 cm × 4–8 mm), involucres mostly hemispheric, usually much less than 1 cm high or wide, bright orange ray corollas (white-rayed and other color variants known in cultivation), and lobes of disc flowers glabrous or nearly so. Hybrids between Z. angustifolia and Z. violacea are known in the horticultural trade.
The lack of articulation of the corolla tubes in the ray florets of Zinnia verticillata Andrews (= Z. peruviana) and the bilateral disposition of vascular bundles (continuous with vasculature of the ovary walls) in the ray florets led D. Don (1830) to conclude that true ray “corollas” in Zinnia are lacking, being replaced instead by de novo petaloid structures that mimic ray corollas of other Compositae.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
1. Ray florets usually 5–21 (more in "double" cultivars), sometimes 0 (in Zinnia anomala, subshrubs or shrublets to 12 cm, leaves linear, Texas), corollas usually yellow to orange, sometimes purple, red, or whitish (usually persistent, sessile, becoming papery) | → 2 |
1. Ray florets usually (2–)5–35, sometimes 0, corollas usually yellow to orange, sometimes white (seldom sessile, laminae usually borne on tubes, never persistent and becoming papery) | → 4 |
2. Leaf margins serrate to coarsely toothed | Heliopsis |
2. Leaf margins entire | → 3 |
3. Leaves petiolate or sessile; cypselae ± terete or obscurely 3–4-angled to compressed or flattened (all usually tuberculate and usually bearing uncinate hairs, none, some,or all in each head winged) | Sanvitalia |
3. Leaves sessile; cypselae 3-angled or flattened (none with uncinate hairs, none winged) | Zinnia |
4. Disc florets functionally staminate (only ray florets produce cypselae) | → 5 |
4. Disc florets bisexual, fertile | → 9 |
5. Phyllaries 8–10 in 2 series | → 6 |
5. Phyllaries 12–45+ in (2–)3–4 series | → 7 |
6. Perennials; leaves opposite, petiolate, margins crenate | Chrysogonum |
6. Annuals; leaves mostly alternate (distal sometimes opposite), ± sessile, margins coarsely toothed (mostly distal 1/2) | Lindheimera |
7. Ray florets 8–35 (in 1–3 series); cypselae (shed alone without accessory structures) | Silphium |
7. Ray florets usually (2–)8(–13); cypselae (each shed together with subtending phyllary and 2–4 adjacent paleae and disc florets) | → 8 |
8. Phyllaries usually 14–22 in 2–3 series (broadly obovate to orbiculate, without linear appendages); ray corollas pale yellow to orange-yellow (abaxially red to maroon or with greenish or red to maroon veins) | Berlandiera |
8. Phyllaries 18–24+ in ± 3 series (at least outer with relatively short, expanded, indurate bases and longer, linear, herbaceous tips); ray corollasyellow (without notably colored veins) | Engelmannia |
9. Leaves mostly basal, or basal and cauline, or cauline, mostly alternate | → 10 |
9. Leaves mostly cauline, mostly opposite | → 21 |
10. Cypselae prismatic, or nearly so, 3–4-angled | → 11 |
10. Cypselae compressed to flattened | → 15 |
11. Ray florets usually 8–21 (corollas mostly pink, red, purple, or white, yellow in E. paradoxa var. paradoxa, laminae often drooping or reflexed);receptacles mostly conic (heights often 2+ times diams.) | Echinacea |
11. Ray florets (1–)5–25+ (corollas yellow or orange, laminae not drooping or reflexed), sometimes 0; receptacles flat to convex | → 12 |
12. Leaves mostly basal (cauline usually notably smaller than basal); pappi 0 | Balsamorhiza |
12. Leaves basal and cauline, or mostly cauline; pappi usually coroniform, sometimes of 1–4+ scales or 0 | → 13 |
13. Leaves mostly cauline (blades narrowly oblong to linear, 5–25 mmwide) | Scabrethia |
13. Leaves basal and cauline, or mostly cauline (blades mostly 30–120 mm wide) | → 14 |
14. Leaves mostly elliptic, lanceolate, or oblong (basal and cauline, basal usually notably larger than cauline, cauline mostly sessile) | Wyethia |
14. Leaves mostly orbiculate, ovate, or rounded-deltate (mostly cauline, mostly petiolate, proximal and distal usually ± similar) | Agnorhiza |
15. Cypselae winged; pappi persistent, of 2(–3) scales (scales often aristate or subulate, without additional scales) | Verbesina |
15. Cypselae sometimes thin-edged (margins sometimes ciliate or corky-thickened, never truly winged); pappi usually of (1–)2, subulate scales or bristlelike awns plus 2–4+ shorter scales, sometimes 0 (rarely of 2–3 aristate scales without additional scales) | → 16 |
16. Perennials (scapiform); leaves all or mostly basal; involucres 20–30+ mm diam | Enceliopsis |
16. Perennials (rarely scapiform), subshrubs, or shrubs; leaves usually cauline, sometimes basal and cauline; involucres 4–30 mm diam | → 17 |
17. Perennials (rhizomatous); leaves linear to filiform | Phoebanthus |
17. Perennials or shrubs (not rhizomatous); leaves mostly deltate, elliptic, lanceolate, or ovate (and most intermediate shapes, not linear to filiform) | → 18 |
18. Ray florets 8–21, pistillate and fertile | Helianthella |
18. Ray florets 0 or 8–40, neuter, or styliferous and sterile | → 19 |
19. Subshrubs or shrubs (glabrous or ± scabrellous, usually vernicose); phyllaries 12–40 in 2–4+ series (subequal or unequal, outer longer) | Flourensia |
19. Annuals, perennials, or shrubs (glabrous or canescent, hirtellous, scabrellous, strigose, or tomentose, often gland-dotted or glandular-puberulent to stipitate-glandular, seldom vernicose); phyllaries 18–30(–50+) in 2–3+ series (subequal or unequal, outer shorter) | → 20 |
20. Perennials (E. nutans), subshrubs, or shrubs; pappi usually 0, sometimes fragile, of 2 weak, villous scales | Encelia |
20. Annuals or perennials; pappi usually persistent, of 2 subulate scales | Geraea |
21. Heads discoid (corollas white or whitish); pappi 0, or readily falling, of 2–12 barbellate bristles or awns | Melanthera |
21. Heads radiate or discoid (corollas seldom white or whitish); pappi 0, or usually persistent and coroniform or cyathiform (each an erose, fimbriate, or lacerate cup, with or without additional awns or bristles, borne on rostrums), or of 2–4+ awns, bristles, and/or scales | → 22 |
22. Pappi usually coroniform or cyathiform (cypselae often rostrate, each with apical boss or neck), sometimes 0 (prostrate perennials) | → 23 |
22. Pappi usually of 2–4+ awns, bristles, and/or scales (not cyathiform, cypselae not rostrate), sometimes coroniform or 0 (not prostrate perennials) | → 24 |
23. Subshrubs or shrubs (erect); cypselae (some or all) strongly compressed, nota-bly winged | Wedelia |
23. Perennials (prostrate); cypselae strongly biconvex to plumply 3–4-angled (not com-pressed, not winged, epidermes usually corky, often tuberculate) | Sphagneticola |
24. Some or all cypselae winged (each bordered by wing of membranous or corky tissue different from that of body of cypsela) | → 25 |
24. Cypselae sometimes sharp-edged (not winged) | → 27 |
25. Heads in glomerules or borne singly (sessile or subsessile in axils); cypselaewinged (rays, not discs, wings lacerate) | Synedrella |
25. Heads borne singly or in corymbiform, dichasiiform, or paniculiform arrays (not sessile); cypselae winged (rays and discs, wings not lacerate) | → 26 |
26. Phyllaries 9–30 in 1–4 series (outer 2–5 similar to others, unlike foliage); pappi of 2(–3) persistent (often aristate or subulate) scales without additional scales | Verbesina |
26. Phyllaries 26–38+ in 3–4+ series (outer 2–6+ similar to foliage in shape, texture, and indument); pappi of 2–3 fragile or persistent awns or subulate scales plus 2–8+, distinct or basally connate, erose or lacerate scales (often each cypsela with additional seta on inner shoulder) | Jefea |
27. Cypselae 3–4-angled (weakly or not at all compressed or obcompressed, epidermes usually thick, corky) | → 28 |
27. Cypselae (all or at least disc) strongly compressed or obcompressed or flattened (epidermes seldom thick and corky) | → 30 |
28. Corollas white or whitish (paleae linear-filiform, not conduplicate) | Eclipta |
28. Corollas yellow to orange (paleae lanceolate to ovate, conduplicate) | → 29 |
29. Leaves elliptic, linear, oblanceolate, obovate, or ovate, glabrous or puberulent to villous and/or sericeous (outer phyllaries elliptic, oblanceolate, or ovate) | Borrichia |
29. Leaves lanceolate to lance-linear, sparsely scabrous (outer phyllaries lance-linear to linear) | Pascalia |
30. Annuals or perennials (mostly 5–30+ cm; larger leaves mostly 1–5+ cm); involucres 3–8 mm diam.; phyllaries 5 in 1(–2) series, or 8–15+ in 1–3 series | → 31 |
30. Perennials (coarse, 10–150 cm; larger leaves mostly 5–25 cm); involucres 10–30 mm diam.; phyllaries 12–35 in 2–5 series | → 32 |
31. Disc florets 25–100(–200+); receptacles conic; cypselae ellipsoid to obovoid; pappi 0, or fragile, of 1–3 bristlelike awns | Acmella |
31. Disc florets 10–20; receptacles convex; cypselae cuneate; pappi of 2(–5+) stout awns | Calyptocarpus |
32. Leaf blades oblanceolate to lanceolate or lance-linear (longer usually 8–25 cm), margins entire | Helianthella |
32. Leaf blades rounded-deltate to ovate or lance-ovate (longer usually 5–8 cm),margins coarsely serrate | Lasianthaea |
1. Annuals, 30–50(–200) cm; leaf blades elliptic, lanceolate, oblong, or ovate; involucres campanulate, or hemispheric or broader, 10–25 mm diam | → 2 |
1. Subshrubs, to 22 cm; leaf blades linear to acerose; involucres narrowly campanulate, cylindric, or subhemispheric, 5–10mm diam | → 3 |
2. Involucres narrowly to broadly campanulate, 9–18 × 10–20 mm; paleae apically obtuse, erose or subentire; pappi usually of 1 awn (disc cypselae) | Z. peruviana |
2. Involucres hemispheric or broader, 10–15 × 15–25 mm; paleae apically fimbriate; pappi 0 | Z. violacea |
3. Leaf blades 1-nerved, linear to acerose; ray florets 4–7, corollas usually white, sometimes pale yellow | Z. acerosa |
3. Leaf blades 1- or 3-nerved (some larger leaves), linear; ray florets usually 5–8, corollas usually yellow (laminae sometimes 0) | → 4 |
4. Involucres 8–10 mm; ray laminae 0–6(–9) mm | Z. anomala |
4. Involucres 5–8 mm; ray laminae mostly 10–18 mm | Z. grandiflora |
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