Saxifragaceae
Saxifraga
saxifrage family
saxifrage
appearing in spring, summer, or autumn with leaves usually present (usually appearing in autumn or winter after basal leaves have withered in Jepsonia), leafless, or leafy and bearing 1–5 cauline leaves proximally, glabrous or short to long stipitate-glandular or eglandular, hairs usually multicellular (unicellular in Astilbe, Saxifragopsis).
± erect, leafy, 1–40[–100] cm.
usually in basal rosettes, sometimes cauline, usually alternate, sometimes opposite (Chrysosplenium, Lithophragma, Mitella, Saxifraga), usually simple (compound in Astilbe, sometimes compound in Lithophragma, Tiarella);
stipules absent or present;
petiole absent or present, usually not jointed distally at attachment to blade (jointed distally in Saxifragopsis), usually not peltate (peltate in Darmera), not producing adventitious buds at apices of petioles of basal rosette and cauline leaves (usually producing adventitious buds at apices of petioles in Tolmiea);
blade margins entire, crenate, serrate, or dentate, ciliate or glandular-ciliate.
in basal rosette and cauline, alternate (opposite in S. nathorstii, S. oppositifolia), cauline reduced;
stipules absent;
petiole absent or present;
blade obovate, oblong, oblong-obovate, elliptic, linear, spatulate, or oblanceolate to ovate, reniform, or round, lobed or unlobed, base cuneate to cordate, ultimate margins entire, crenate, serrate, or dentate, (with lime-secreting hydathodes in S. aizoides, S. nathorstii, S. oppositifolia, S. paniculata), apex acute to obtuse or rounded;
venation pinnate or palmate.
usually terminal racemes, panicles, cymes (simple or compound), thyrses (with lateral dichasial or monochasial cymose branches), or solitary flowers (Chrysosplenium, Lithophragma), sometimes axillary cymes (Chrysosplenium), usually arising from terminal or axillary buds in rosettes, 2–300(–1000+)-flowered, bracteate or ebracteate.
thyrses or, sometimes, cymes, sometimes solitary flowers, terminal from terminal bud in rosette, 2–200[–1000]-flowered, (some or all flowers replaced by bulbils in S. cernua, S. mertensiana), usually bracteate (ebracteate in S. nathorstii, S. oppositifolia); (bracts leaflike).
usually bisexual, sometimes unisexual (Astilbe, Saxifraga), homostylous (heterostylous in Jepsonia), usually radially symmetric, sometimes bilaterally symmetric (Bensoniella, Heuchera, Micranthes, [Saxifraga], Tiarella, Tolmiea);
perianth and androecium hypogynous, perigynous, or epigynous;
hypanthium free (Bolandra, Jepsonia) or ± adnate to ovary, usually not split to base (split to base in Tolmiea);
sepals usually (4–)5(–6), distinct;
petals usually (4–)5(–6) or absent, distinct, lobed or unlobed;
nectary disc often encircling ovary distally at junction of ovary and free portion of hypanthium;
stamens (2–)5(–9)10;
anthers usually dehiscent longitudinally, rarely by broad terminal openings (Leptarrhena);
staminodes absent;
pistils 1, sometimes appearing 2–3+ (Micranthes), usually 2-carpellate, rarely 3-carpellate (Astilbe, Lithophragma, Micranthes), carpels connate for full length of ovary to barely connate proximally, equal, rarely unequal (Tiarella);
ovary superior to inferior, 1–2(–3)-locular, ovaries fully connate when 1-locular, proximally connate to varying degrees when 2- and 3-locular (Astilbe, Micranthes);
placentation axile, appearing marginal when ovaries are barely connate, or parietal;
ovules anatropous, usually bitegmic, rarely unitegmic (most Micranthes), crassinucellate;
styles 2–3(–4), distinct or connate (Saxifragopsis);
stigmas 2–3(–4), capitate.
[bilaterally symmetric], bisexual (unisexual and plants sometimes gynodioecious, or plants dioecious in S. eschscholtzii);
hypanthium free from or 1/4–3/4 adnate to ovary, free from ovary to 0.5 mm, green or pink to purple, (0.1–4 mm);
sepals 5, green, sometimes reddish at tips, sometimes ± purple;
petals absent or (1–)5, white, cream, yellow, orange, red, pink, or purple, often yellow-, orange-, or red-spotted;
nectary disc present or not;
stamens 10, (distinct);
filaments linear and ± flattened (club-shaped in S. mertensiana);
ovary superior to ± inferior, sometimes appearing more superior in fruit, 2-locular, carpels usually (1/4–)1/2 connate proximally or ± distinct;
placentation axile (when connate 1/2+ their length) or appearing marginal;
styles 2;
stigmas 2.
capsular, sometimes folliclelike (Cascadia, Micranthes), 2–3(–4)-beaked, equally valvate (unequally valvate in Tiarella), dehiscence septicidal between beaks.
2(–3)-beaked (± folliclelike in S. oppositifolia).
5–200, tan, brown, dark brown, black, yellowish brown, reddish brown, or red, rarely winged (Astilbe, Jepsonia, Sullivantia), ellipsoid, fusiform, ovoid, oblong, spheroid, oblong-cylindric, flat, or straight on 1 side, convex on other, rarely prismatic, smooth, wrinkled, ribbed, papillate, pitted, or ridged, tuberculate, warty, spiny, cellular-rugulose, or muricate;
embryo straight;
endosperm oily, copious.
brown, oblong, ellipsoid, or ovoid, smooth, tuberculate, or papillate.
= 6, 8, 11, 13, 14.
Saxifragaceae
Saxifraga
Genera ca. 38, species ca. 600 (23 genera, 158 species in the flora).
Classification of Saxifragaceae has been varied and controversial (e.g., A. Cronquist 1981; H. G. A. Engler 1930; J. Hutchinson 1973; G. K. W. Schulze-Menz 1964b; A. L. Takhtajan 1997; R. F. Thorne 1992). Molecular phylogenetic data (D. R. Morgan and D. E. Soltis 1993; Soltis et al. 1993, 2001; Angiosperm Phylogeny Group 1998, 2003) reveal that genera of Saxifragaceae in the broad sense are allied with at least ten separate, often distantly related families of flowering plants. These data also suggest that Saxifragaceae in the narrow sense as treated here consists of about 38 genera worldwide, equivalent to subfamily Saxifragoideae, one of the 15 subfamilies recognized by Engler and one of the 17 recognized by Schulze-Menz of the broadly defined Saxifragaceae. Molecular phylogenetic data (Soltis et al. 2001) show that the narrowly defined Saxifragaceae fall into two major groups: Saxifraga, and the heucheroid clade encompassing all other genera. Molecular data further show that Saxifraga, as traditionally understood, is polyphyletic, comprising two distinct lineages (treated here as Saxifraga and Micranthes) and the monospecific North American Cascadia. The major split between Saxifraga and the heucheroid clade is supported not only by molecular data from six DNA regions but by differences in patterns of floral morphology. Saxifraga has a relatively uniform floral morphology (radially symmetric flowers, with bilateral symmetry restricted to one Asian group of species, which consistently have the same number of sepals, petals, stamens, and carpels). Almost all of the variation in the family in numbers of sepals, petals, stamens, and carpels occurs in the heucheroid clade. Radially symmetric flowers predominate there, but some bilateral flowers are found in Bensoniella, Micranthes, Tolmiea, and some species of Heuchera.
Penthorum, the only genus in Penthoroideae of Saxifragaceae (H. G. A. Engler 1930), is morphologically anomalous in the Saxifragaceae and has often been included in Crassulaceae or, as treated here, its own family, Penthoraceae (Angiosperm Phylogeny Group 1998). Itea and Ribes, sole members of Iteoideae and Ribesoideae, respectively, are treated here as separate families, Iteaceae and Grossulariaceae. Crassulaceae, Grossulariaceae, Iteaceae, Paeoniaceae, Penthoraceae, and Saxifragaceae belong to the Saxifragales, as treated here, as well as Altingiaceae, Cercidiphyllaceae, Daphniphyllaceae, Haloragaceae (which includes Penthoraceae and Tetracarpaeaceae), Hamamelidaceae, Peridiscaceae, and Pterostemonaceae (Soltis et al. 2005).
Carpenteria, Decumaria, Deutzia, Fendlera, Fendlerella, Hydrangea, Jamesia, Philadelphus, and Whipplea once belonged to Hydrangeoideae of Saxifragaceae (H. G. A. Engler 1930) and are treated in the flora as Hydrangeaceae. Escallonia, the sole genus of Escallonioideae (Engler), is treated in the flora as Escalloniaceae. Molecular, morphological, and chemical data (C. R. Bensel and B. F. Palser 1975, 1975b, 1975c, 1975d; B. A. Bohm et al. 1988; M. L. Haskins and W. J. Hayden 1987; L. Hufford and W. C. Dickison 1992; D. R. Morgan and D. E. Soltis 1993; Soltis and B. A. Bohm 1982; Soltis et al. 1993; Soltis and P. S. Soltis 1997; Angiosperm Phylogeny Group 1998, 2003) indicate that Hydrangeaceae and Escalloniaceae are more likely to be related to the asterids, within which Hydrangeaceae appears to be close to Cornales.
Parnassia and Lepuropetalon have been included in Saxifragaceae as the subfamily Parnassioideae in the past (A. Cronquist 1981; H. G. A. Engler 1930; J. Hutchinson 1973; S. A. Spongberg 1972). Based on molecular, morphological, and chemical data, these genera appear to be only distantly related to other genera of Saxifragaceae and are here moved to Parnassiaceae (C. R. Bensel and B. F. Palser 1975, 1975b, 1975c, 1975d; B. A. Bohm et al. 1986; D. R. Morgan and D. E. Soltis 1993; Soltis et al. 2001; A. L. Takhtajan 1969; R. F. Thorne 1992). Molecular phylogenetic analyses (M. W. Chase et al. 1993; Zhang L. B. and M. P. Simmons 2006) have aligned Parnassiaceae with Celastraceae, either as a sister family or as a basal member of Celastraceae.
Molecular systematic studies have revealed that the approximately 38 remaining genera form a strongly supported clade (D. E. Soltis et al. 1993, 2000; Soltis and P. S. Soltis 1997; S. B. Hoot et al. 1999; V. Savolainen et al. 2000) that corresponds to the Saxifragoideae of Engler and is identical to the family circumscriptions of A. L. Takhtajan (1969, 1997) and R. F. Thorne (1992).
H. G. A. Engler’s (1930) subfamily Saxifragoideae contained one tribe, Saxifrageae, which consisted of four subtribes: Astilbinae, Leptarrheninae, Saxifraginae, and Vahliinae. Vahliinae is now known to be very distantly related to the Saxifragaceae. G. K. W. Schulze-Menz (1964b) elevated three of Engler’s subtribes to tribes: Astilbeae, Leptarrheneae, and Saxifrageae. K. Klopfer (1973) later recognized two large groups, one centered around Heuchera having parietal placentation, another centered around Saxifraga having axile placentation. Recent molecular phylogenetic and systematic studies indicate the presence of six well-marked clades, informally recognized as the Astilbe, Boykinia, Chrysosplenium, Darmera, Heuchera, and Leptarrhena groups (reviewed in Soltis et al. 2001). Relationships within some of these groups (e.g., the Boykinia and Heuchera groups) have also been studied in detail from a phylogenetic standpoint (e.g., Soltis and R. K. Kuzoff 1995; Soltis et al. 1997).
During fruit development in some genera (especially Saxifraga and Lithophragma), partially to mostly inferior ovaries swell to become increasingly superior due to allometric shifts (R. K. Kuzoff et al. 2001). Ovary position in keys and descriptions here refers to flowers during or shortly after anthesis. Reports of variation in ovary position in some genera and species may be due to observations of flowers at different developmental stages. D. E. Soltis et al. (2005) reported that most genera of Saxifragaceae display appendicular epigyny in floral development, which begins with a minute convex floral apex. During or after perianth initiation, the floral apex becomes concave, giving rise to an inferior ovary. Ovaries in Saxifragaceae often appear to be nearly superior or one-half to three-fourths inferior, but with their appendicular epigynous ground plan, they are not truly superior or homologous to superior ovaries. Instead, they are “superior mimics” with “pseudosuperior” ovaries.
Species in some North American genera (particularly Boykinia, Darmera, Heuchera, Micranthes, Saxifraga, Tellima, Tiarella, and Tolmiea) are popular horticultural subjects.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Antiphylla Haworth; Heterisia Rafinesque ex Small; Hirculus Haworth; Leptasea Haworth; Lobaria Haworth; Muscaria Haworth
Species ca. 390 (25 in the flora).
Saxifraga has had differing treatments (e.g., J. K. Small and P. A. Rydberg 1905b; H. G. A. Engler and E. Irmscher 1916; P. E. Elvander 1984; D. A. Webb and R. J. Gornall 1989). Most have been based on morphology and cytology. Relationships among species are difficult to assess. The broad Linnaean concept of the genus had been accepted by most recent authors. Molecular phylogenetic data (summarized by D. E. Soltis et al. 2001) show that Saxifraga as traditionally understood is polyphyletic and should be divided into two main groups, Saxifraga in the narrow sense and Micranthes Haworth, the treatment followed here. Other taxa, notably the North American Cascadia, must also be recognized. Cascadia differs from both Saxifraga and Micranthes in its lax, trailing stems and only cauline leaves, its carpels connate only proximally and each independently adnate to the hypanthium, and its spiny seeds; its ovules are bitegmic as in Saxifraga; ovules are unitegmic (except for sect. Merkianae) in Micranthes. In addition, Saxifraga and Micranthes differ by the following traits: leaves basal and cauline (these sometimes reduced and bractlike) in the former versus basal only (or proximally crowded) in the latter (the flowering stems being leafless); carpels usually connate more than one-half versus less than one-half, although there is variation in both genera for this trait; seeds smooth, tuberculate, or papillate versus longitudinally ribbed; and pollen striate or granular versus reticulate (L. Brouillet and R. J. Gornall 2007).
Saxifraga in the narrow sense, as adopted here, includes most sections of the traditional genus as well as a majority of the species. In North America fewer species belong to Saxifraga than to Micranthes. Eight species of Saxifraga are endemic to North America. A single introduced species has established itself in the flora area; other garden species have usually not escaped or were ephemeral. The following species are excluded from this treatment: S. cymbalaria Linnaeus (misidentification of S. sibthorpii Boissier, a garden plant, not established), S. ×geum Linnaeus and S. umbrosa Linnaeus (both misidentifications of S. hirsuta specimens), and S. hirsuta Linnaeus (not established). The report of S. stolonifera Meerburgh (syn. S. sarmentosa Linnaeus f.) from California is old; there has been no recent collection, and that species also is excluded here.
There is extensive occurrence of polyploidy and dysploidy throughout Saxifraga (P. E. Elvander 1984; D. A. Webb and R. J. Gornall 1989).
The stigmas and styles are typically two; occasional flowers on plants in some species have three or, rarely, four stigmas and styles. In addition, ovary position in some taxa can change from mostly inferior at flowering to superior in fruit. Ovary position is described at flowering. Capsules usually have two connate carpels that are distally distinct; in rare cases, carpels are distinct nearly to the base and fruits are folliclelike. Only such exceptions are indicated in descriptions, the usual case being assumed.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
1. Leaves ternately decompound or 3-pinnately compound, never simple; flowers usually unisexual, sometimes bisexual; inflorescences plumose panicles, relatively large, branched, rarely congested and spikelike. | Astilbe |
1. Leaves usually simple, rarely compound; flowers usually bisexual; inflorescences solitary flowers or racemes, panicles, simple or compound cymes, or thyrses | → 2 |
2. Sepals 4; petals absent; stamens 2-8, usually 4 or 8; hypanthia greenish or yellow-green. | Chrysosplenium |
2. Sepals 5(-6); petals (1-)4-5 or absent; stamens 3, 5(-6), or 10; hypanthia usually green, greenish, white, cream, yellow, yellowish green, pink to red or purple, or pinkish to reddish purple | → 3 |
3. Stamens 3; petals 4; hypanthia ± split to base; adventitious buds usually produced at apices of petioles of basal rosette and cauline leaves, sometimes forming plantlets. | Tolmiea |
3. Stamens usually 5 or 10; petals usually 5 or absent; hypanthia not split to base; adventitious buds and plantlets not present at apices of petioles of basal and cauline leaves | → 4 |
4. Leaves peltate. | Darmera |
4. Leaves not peltate | → 5 |
5. Flowers heterostylous (stamens proximal to stigmas in some plants, distal in others); flowering in autumn(-winter) after basal leaves have withered, rarely flowers and leaves present together. | Jepsonia |
5. Flowers homostylous; flowering in spring, summer, or autumn with leaves usually present | → 6 |
6. Placentation parietal; ovaries 1-locular; inflorescences terminal from axillary buds in rosettes | → 7 |
6. Placentation axile or marginal; ovaries 2-3-locular; inflorescences terminal from terminal buds in rosettes | → 15 |
7. Stamens 10; inflorescences usually racemes or panicles, sometimes solitary flowers | → 8 |
7. Stamens 5(-6); inflorescences racemes or thyrses, sometimes resembling panicles or spikes | → 11 |
8. Styles 3; pistils 3-carpellate; sometimes with bulbils in axils of cauline leaves. | Lithophragma |
8. Styles 2; pistils 2-carpellate; bulbils absent in axils of cauline leaves | → 9 |
9. Capsules unequally valvate; petals unlobed; ovaries superior; leaves simple or 3-foliolate. | Tiarella |
9. Capsules equally valvate; petals lobed; ovaries 1/4-1/2 inferior or nearly superior; leaves simple | → 10 |
10. Petals 5-7-lobed; flowering stems 40-90 cm; hypanthia 4.5-9 mm; styles 1-1.5 mm; cauline leaves 2-3. | Tellima |
10. Petals 9-11(-15)-lobed; flowering stems (2-)8-48 (-60) cm; hypanthia (0.6-)0.8-2.7 mm; styles 0.1-0.6 mm; cauline leaves absent or 1-3. | Mitella |
11. Inflorescences thyrses (with cymose side branches), sometimes diffuse (resembling panicles) or dense (resembling spikes); petals unlobed, sometimes absent. | Heuchera |
11. Inflorescences racemes; petals unlobed or lobed, rarely absent | → 12 |
12. Hypanthia 5-9 mm; ovaries 1/4 inferior; petals 4-7-lobed, rarely ± unlobed; rocky ledges, cliffs, alpine open slopes, talus slopes; British Columbia, Oregon, Washington. | Elmera |
12. Hypanthia 0.6-4 mm; ovaries 1/3 to nearly completely inferior; petals 3-11-lobed or unlobed, sometimes absent; moist sites and fir forests from Alaska, British Columbia, and Yukon to Alberta, California, Colorado, Oregon, South Dakota, and Utah, rocky slopes in the Rocky Mountains | → 13 |
13. Styles 0.1-1.1 mm; petals usually 3-11-lobed, sometimes unlobed; hypanthia 0.6-2.7 mm; moist sites; Alaska to South Dakota, Utah, Colorado, California. | Mitella |
13. Styles absent or 2-3 mm; petals usually unlobed, sometimes absent; hypanthia 2-4 mm; wet meadows, fir forests in California and Oregon, rocky slopes in the Rocky Mountains | → 14 |
14. Styles 2-3 mm; petals linear, sometimes coiled, sometimes absent; hypanthia campanulate; capsules (1.8-)2-2.7 mm; ovaries 1/3 inferior; wet meadows, fir forests; California, Oregon. | Bensoniella |
14. Styles absent; petals elliptic to narrowly spatulate; hypanthia cylindric to obconic; capsules 6.5-10 mm; ovaries 1/2-3/4 inferior; rocky slopes; Rocky Mountains from Alberta to Colorado. | Conimitella |
15. Stamens 5 | → 16 |
15. Stamens 10 | → 19 |
16. Plants bearing bulbils at base of slender caudices, without rhizomes or stolons | → 17 |
16. Plants not bearing bulbils at bases of caudices, rhizomatous and, sometimes, stoloniferous | → 18 |
17. Sepals 3-10 mm; hypanthia 4-10 mm; capsules 8-11 mm; styles 1-2 mm; ovaries nearly superior; petals narrowly lanceolate, greenish with purple margins or reddish purple to dark purple. | Bolandra |
17. Sepals 1.5-3.5 mm; hypanthia 2.5-3.5 mm; capsules 4-7 mm; styles absent or to 1 mm; ovaries 1/2-3/4 inferior; petals elliptic to obovate, white or pink, purple, or violet. | Suksdorfia |
18. Seeds linear-fusiform, narrowly wing-margined, surfaces smooth; flowering stems and petioles glabrate or sparsely stipitate-glandular; cauline leaves glabrate; ovaries 1/2-4/5 inferior; petals 1.6-3.5 mm. | Sullivantia |
18. Seeds ellipsoid, not winged, surfaces usually tuberculate, smooth in 1 species; flowering stems and petioles usually densely stipitate-glandular and eglandular-pubescent; cauline leaves stipitate-glandular; ovaries 2/3 to completely inferior; petals 2-12(-15) mm. | Boykinia |
19. Anthers dehiscent by broad, terminal openings; carpels connate proximally; seeds fusiform, ribbed (at least over embryo). | Leptarrhena |
19. Anthers dehiscent by longitudinal slits; carpels usually connate in proximal 1/4-1/2; seeds oblong, ovoid, or ellipsoid, smooth, ribbed, tuberculate, papillate, or spiny | → 20 |
20. Hypanthia free from ovary 1-3.5 mm; stipules expanded from petiole bases; petals crimson-purple to violet-purple | Telesonix |
20. Hypanthia completely adnate to ovary or free from ovary to 0.2 mm; stipules barely expanded or absent; petals white, cream, greenish, yellow, yellowish green, orange, red, pink, or purple, sometimes red-tinged or with purple margins or tips; sepals usually green, sometimes purple, sometimes reddish at tips | → 21 |
21. Petioles jointed distally at attachment to leaf blades, separating early from blades; hairs unicellular; Siskiyou Mountains of California and Oregon, and sometimes in Washington. | Saxifragopsis |
21. Petioles not jointed distally at attachment to leaf blades, not separating from blades; hairs multicellular, or plants glabrous; widespread, mostly north-temperate, arctic, and alpine regions | → 22 |
22. Leaves cauline; flowering stems trailing or suberect, leafy; carpels connate proximally; seeds spiny; Coast Range to the western slopes of the Cascade Range from extreme nw California to sw Washington. | Cascadia |
22. Leaves basal, or basal and cauline; flowering stems ± erect, leafless or leafy; carpels connate in proximal 1/2; seeds smooth, tuberculate, papillate, or ribbed; mostly north-temperate, arctic, and alpine regions | → 23 |
23. Leaves usually basal; flowering stems usually leafless, rarely leaves crowded proximally at base of flowering stems; seeds ribbed. | Micranthes |
23. Leaves basal and cauline; flowering stems usually with reduced cauline leaves; seeds smooth, tuberculate, or papillate. | Saxifraga |
1. Inflorescences with all or some flowers replaced by bulbils | → 2 |
1. Inflorescences without bulbils | → 3 |
2. Basal leaves usually ephemeral (gradually dying through growing season), leaf blade (3-)5-18(-20) mm, 3-7(-9)-lobed, margins entire; inflorescences with bulbils often replacing all flowers or all flowers except terminal; bracts conspicuous; sepals erect. | S. cernua |
2. Basal leaves persistent, leaf blade 20-80(-100) mm, irregularly lobed, margins serrate; inflorescences with bulbils replacing at least some flowers; bracts ± inconspicuous; sepals reflexed (at least in fruit). | S. mertensiana |
3. Ovaries 1/2+ inferior (sometimes appearing more superior in fruit) | → 4 |
3. Ovaries ± superior to ca. 1/2 inferior | → 13 |
4. Petals yellow to orange | → 5 |
4. Petals white, cream, pink, or purple, yellowish, greenish, or pink tinged | → 6 |
5. Plants mat- or cushion-forming, not stoloniferous; leaf blade margins usually spinose-ciliate; inflorescences glabrous or clear-tipped stipitate-glandular. | S. aizoides |
5. Plants in clumps, stoloniferous; leaf blade margins glandular-ciliate; inflorescences purplish-tipped stipitate-glandular. | S. flagellaris |
6. Petioles absent; leaf blades leathery, lime-secreting hydathodes present. | S. paniculata |
6. Petioles usually present; leaf blades thin or ± fleshy (not leathery), lime-secreting hydathodes absent | → 7 |
7. Leaf blades spatulate, obovate, oblanceolate, or elliptic to ovate | → 8 |
7. Leaf blades reniform to orbiculate or round | → 10 |
8. Plants perennial, densely cushion- or loosely mat-forming. | S. cespitosa |
8. Plants biennial or annual, solitary or tufted | → 9 |
9. Plants biennial, basal leaves persistent; petals (2-)3-6 mm. | S. adscendens |
9. Plants annual, basal leaves usually withered at flowering; petals 2.5-3 mm. | S. tridactylites |
10. Plants usually densely (sometimes loosely) tufted, not rhizomatous | → 11 |
10. Plants loosely (sometimes densely) tufted or matted, sometimes solitary, rhizomatous | → 12 |
11. Cauline leaves 3-5 (proximal similar to basal leaves); hypanthium V-shaped in longisection, glabrous or sparsely short stipitate-glandular; sepals 0.7-1 mm wide. | S. debilis |
11. Cauline leaves 1-3 (dissimilar from basal leaves, reduced); hypanthium U-shaped in longisection, sparsely to densely long stipitate-glandular; sepals 1.5-2.1 mm wide. | S. hyperborea |
12. Plants green; leaf blades (5-)7.4-11.2(-20) mm, 5-7(-11)-lobed, lobes obtuse, sometimes acute; inflorescences capitate thyrses (flowers subsessile), (3-)5-15(-18) cm; bracts 5-10, leaflike, 3-7-lobed, densely surrounding inflorescence; petals broadly elliptic to obovate. | S. bracteata |
12. Plants green to purple; leaf blades (2.6-)3.7-5.2(-7.4) mm, 3-5(-7)-lobed, lobes rounded, sometimes ± obtuse; inflorescences cymes (flowers pedicellate), 1.7-7 cm; bracts 2-3, reduced, unlobed or 1-3-lobed, not surrounding inflorescence; petals oblong to elliptic. | S. rivularis |
13. Leaves mostly opposite, with lime-secreting hydathodes | → 14 |
13. Leaves alternate, without lime-secreting hydathodes | → 15 |
14. Leaf blades oblong to obovate, 2-5 mm; petals purple to pink, rarely white, often drying violet. | S. oppositifolia |
14. Leaf blades oblanceolate to elliptic, 5-9 mm; petals salmon to flesh colored, sometimes red or orange, rarely yellow, sometimes violet tinged. | S. nathorstii |
15. Petals yellow to greenish yellow (rarely purple), rarely orange- or red-spotted, sometimes fading when dried | → 16 |
15. Petals white or cream to purple, sometimes yellow-, orange-, or red-, or purple-spotted, sometimes drying to cream or pale yellow | → 21 |
16. Plants loosely tufted and rhizomatous or in solitary clumps and stoloniferous | → 17 |
16. Plants mat- or cushion-forming, rhizomatous | → 18 |
17. Plants loosely tufted, not stoloniferous or sometimes shortly so; leaf blade margins eciliate or sparsely reddish brown-ciliate, surfaces glabrous or sparsely reddish brown-villous; sepal margins reddish brown-ciliate. | S. hirculus |
17. Plants in solitary clumps, stoloniferous; leaf blade margins glandular-ciliate, surfaces glabrous; sepal margins stipitate glandular-ciliate. | S. flagellaris |
18. Flowers unisexual; leaf blade margins stiffly bristly-ciliate. | S. eschscholtzii |
18. Flowers bisexual; leaf blade margins ciliate (but not stiffly bristly) or eciliate | → 19 |
19. Petals greenish yellow, 2-3 mm. | S. aleutica |
19. Petals bright golden or pale yellow, rarely purple, 4-8 mm | → 20 |
20. Sepals erect to spreading, margins eciliate or sparsely ciliate; petals pale yellow, rarely purple. | S. serpyllifolia |
20. Sepals strongly reflexed, margins eciliate to glandular-ciliate; petals bright golden yellow. | S. chrysantha |
21. Sepals reflexed (at least in fruit). | S. mertensiana |
21. Sepals erect or ascending to spreading | → 22 |
22. Plants solitary or tufted; leaf blades round to reniform, 3-7(-9)-lobed | → 23 |
22. Plants mat-forming; leaf blades linear or lanceolate to elliptic or oblong, oblanceolate, or obovate to spatulate or cuneate, unlobed or with 1-3 apical teeth or lobes | → 24 |
23. Leaf blades lobed less than halfway to midvein; petioles (5-)10-60 (-90) mm. | S. cernua |
23. Leaf blades lobed usually more than halfway to midvein; petioles 5-15 mm. | S. radiata |
24. Leaf blades usually with 1-3 apical teeth or lobes | → 25 |
24. Leaf blades unlobed | → 27 |
25. Leaf apex long spinose-mucronate, margins softly glandular- ciliate. | S. tricuspidata |
25. Leaf apex mucronate or not, margins stiffly ciliate | → 26 |
26. Leaf blades spatulate, apex mucronate, margins not cartilaginous, unlobed or minutely 3-toothed or -lobed apically; petals red- or orange-spotted distally. | S. vespertina |
26. Leaf blades broadly obovate, apex not or slightly mucronate, margins cartilaginous, prominently 3-lobed apically; petals not spotted. | S. taylorii |
27. Leaf blades linear, linear-lanceolate, or oblanceolate to narrowly elliptic or cuneate, apex acute, spinose-mucronate | → 28 |
27. Leaf blades linear or oblong to oblanceolate or spatulate, apex rounded or obtuse, sometimes mucronate (but not spinose-mucronate) | → 29 |
28. Leaf blade margins stiffly ciliate. | S. bronchialis |
28. Leaf blade margins softly glandular-ciliate. | S. tricuspidata |
29. Petals usually pale yellow, rarely purple, not spotted. | S. serpyllifolia |
29. Petals white to cream, yellow-, orange-, or red- spotted | → 30 |
30. Petals yellow-spotted proximally, red- or orange-spotted distally. | S. vespertina |
30. Petals usually yellow-spotted, sometimes sparsely red-spotted proximally. | S. cherlerioides |
- Local floras:
CA, 
OR - Local Web sites: CalFlora, CalPhotos,
Flora NW, 
PNW Herbaria 
WildflowerSearch
iNaturalist (observations)- LBJ Wildflower Center
- SEINet
- Plants of the World Online
- Encyclopedia of Life
- Wikipedia
- Google Image Search
WA
USDA Plants Database
