Draba juvenilis |
Draba pedicellata |
|
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long-stalk Draba, long-stalk whitlow-grass |
Cusick's Draba, rocky-slope Draba, rocky-slope whitlow-grass, stalk whitlow-cress |
|
Habit | Perennials; (not pulvinate); caudex branched (branches slightly loose, with persistent leaf remains, sometimes terminating in sterile rosettes); often scapose. | Perennials; (loosely cespitose); caudex branched (with persistent leaf bases, branches sometimes terminating in sterile rosettes); scapose. |
Stems | unbranched, (0.3–)0.8–2.3(–3) dm, pubescent proximally, glabrous or sparsely pubescent distally, trichomes simple and 2–4-rayed, 0.07–0.4 mm. |
unbranched, (0.15–)0.3–1.3(–1.6) dm, pubescent proximally, glabrous or nearly so distally, trichomes 2- or 3-rayed and simple, 0.1–1 mm. |
Basal leaves | (loosely) rosulate; petiolate; petiole base ciliate, margin not ciliate, (midvein obscure, trichomes simple and 2-rayed, 0.2–0.7 mm); blade oblanceolate to lanceolate, (0.3–)0.6–2.5(–3.5) cm × (1–)2–7(–10) mm, margins entire or denticulate, surfaces pubescent, abaxially with stalked, cruciform trichomes, 0.2–0.5 mm, adaxially with cruciform and/or simple and 2-rayed ones. |
rosulate; subsessile; blade oblanceolate to obovate, 0.4–1.6(–2) cm × 2–4(–6) mm, margins entire, (not ciliate), surfaces pubescent with stalked, 2–4-rayed trichomes, 0.2–0.9 mm, rarely adaxially with simple trichomes, (midvein obscure abaxially). |
Cauline leaves | 0–2 (or 3); sessile; blade elliptic to ovate or lanceolate, margins usually entire, rarely denticulate, surfaces pubescent as basal adaxially or trichomes predominantly simple. |
0. |
Racemes | (2–)4–13(–18)-flowered, ebracteate, elongated in fruit; rachis not flexuous, glabrous or sparsely pubescent as stem. |
3–20(–27)-flowered, ebracteate, slightly to considerably elongated in fruit; rachis straight or flexuous, usually glabrous, rarely pubescent, trichomes simple and 2–4-rayed. |
Flowers | sepals ovate, 2.2–3 mm, glabrous or pubescent subapically, (trichomes simple and short-stalked, 2-rayed); petals pale yellow to creamy white, spatulate, 3–5 × 1.5–2.5 mm; anthers ovate, 0.4–0.5 mm. |
sepals broadly ovate, 1.8–2.5 mm, glabrous or pubescent, (trichomes simple and branched); petals yellow, spatulate, 3.5–5.5 × 1.5–2.2 mm; anthers ovate, 0.4–0.5 mm. |
Fruiting pedicels | divaricate-ascending or ascending, straight or often curved upward (not expanded basally), (3–)5–17(–22) mm, usually glabrous, rarely pubescent, trichomes simple and stalked, 2–4-rayed. |
divaricate to horizontal, straight or curved upward (expanded basally or not), 4–9(–13) mm, glabrous or pubescent, trichomes simple and 2–4-rayed. |
Fruits | elliptic to oblong or linear-lanceolate, plane (not curved), flattened, 5–11(14) × 2–3 mm; valves usually glabrous, rarely margin pubescent, trichomes simple; ovules 16–30 per ovary; style 0.2–0.7 mm. |
lanceolate to ellipsoid or ovoid, plane (not curved), inflated or slightly flattened, (4.2–)5.3–10(–13) × 2.5–4.5(–5.5) mm; valves glabrous or pubescent, trichomes simple and short-stalked, 2-rayed, 0.05–0.3 mm; ovules 8–16 per ovary; style 0.3–1(–1.2) mm. |
Seeds | oblong, 0.7–1.2(–1.5) × 0.4–0.7(–0.8) mm. |
oblong, 1.2–1.6 × 0.7–0.9 mm. |
2n | = 64. |
= 20. |
Draba juvenilis |
Draba pedicellata |
|
Phenology | Flowering Jun–Jul. | Flowering May–Jul. |
Habitat | Rock outcrops, talus, gravelly beaches and stream banks, meadows, tundra | Rock outcrops, talus, steep gravel slopes in pinyon-juniper, mixed conifer, and subalpine meadow communities |
Elevation | 0-2700 m (0-8900 ft) | 2300-3800 m (7500-12500 ft) |
Distribution |
AK; AB; BC; NT; YT; e Asia (Russian Far East, n Siberia) |
NV; UT
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Discussion | Although Draba kananaskis and D. longipes have often been treated as distinct species, we find no basis for maintaining them. Both exhibit variations in petal color (white to pale yellow) and leaf trichomes (short-stalked to sessile) characteristic of D. juvenilis from the Russian Far East. Perhaps most importantly, all three are octoploids (2n = 64) with x = 8. We conclude that D. kananaskis is nothing more than a minor variant of D. juvenilis and it is treated herein, for the first time, as a synonym of that species. Draba juvenilis is occasionally confused with D. borealis, which also has stalked, cruciform trichomes with unbranched rays. Typical D. juvenilis is easily distinguished from that species by having narrower (2–3 mm) fruits that are glabrous (rarely pubescent) and untwisted, and 0–2 (or 3)-leaved stems. By contrast, D. borealis has wider (2.5–4.5 mm) fruits that are usually pubescent and/or twisted (rarely neither) and (2 or) 3–7(–12)-leaved stems. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Draba pedicellata is known from Elko, Eureka, Nye, and White Pine counties in northeastern Nevada and to Tooele County in northwestern Utah. It was considered a variety of D. cusickii by R. C. Rollins (1993); chromosome number, morphology, and geographic distribution suggest a closer relationship to D. sphaeroides. For a detailed discussion and comparison of these species, consult M. D. Windham (2004). N. H. Holmgren (2005b) divided D. pedicellata into two varieties: var. pedicellata, which is found on limestone throughout the species range, and var. wheelerensis, which is found on non-calcareous substrates in White Pine County. Although var. wheelerensis has slightly more spreading pedicels on somewhat more flexuous rachises, it appears to be little more than a dwarf alpine form of the species. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 7, p. 314. | FNA vol. 7, p. 328. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | D. hirta var. tenella, D. kananaskis, D. longipes | D. cusickii var. pedicellata, D. pedicellata var. wheelerensis |
Name authority | Komarov: Repert. Spec. Nov. Regni Veg. 13: 167. (1914) | (Rollins & R. A. Price) Windham: Madroño 50: 221. (2004) |
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