Draba juvenilis |
Draba globosa |
|
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long-stalk Draba, long-stalk whitlow-grass |
beavertip Draba, rockcress Draba, round-fruit Draba |
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Habit | Perennials; (not pulvinate); caudex branched (branches slightly loose, with persistent leaf remains, sometimes terminating in sterile rosettes); often scapose. | Perennials; (cespitose, pulvinate); caudex branched (with persistent leaves, 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, 0.1–0.5 dm, glabrous. |
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; sessile; blade (not fleshy), narrowly oblanceolate or lanceolate to linear, (0.2–)0.3–0.8 cm × 0.5–1.6(–2) mm, margins entire (ciliate, trichomes simple, 0.1–0.8 mm, apex acute, trichomes usually longer), surfaces glabrous, (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. |
2–5(–7)-flowered, ebracteate, slightly elongated in fruit; rachis not flexuous, glabrous. |
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 (persistent to near fruit maturity), ovate to broadly oblong, 2–3 mm, glabrous; petals white to pale yellow, obovate, 2.5–4 × 1.2–2 mm; anthers oblong, 0.4–0.6 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-ascending, straight or slightly curved, 2–6 mm, glabrous. |
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. |
ovate, plane, flattened, 4.5–8 × 2.5–4 mm; valves (distinctly veined), glabrous; ovules 8–16 per ovary; style (0.1–)0.2–0.6 mm. |
Seeds | oblong, 0.7–1.2(–1.5) × 0.4–0.7(–0.8) mm. |
oblong, 1.1–1.4 × 0.8–1 mm. |
2n | = 64. |
|
Draba juvenilis |
Draba globosa |
|
Phenology | Flowering Jun–Jul. | Flowering Jun–Aug. |
Habitat | Rock outcrops, talus, gravelly beaches and stream banks, meadows, tundra | Ridges, talus, alpine tundra and meadows |
Elevation | 0-2700 m (0-8900 ft) | 2700-3900 m (8900-12800 ft) |
Distribution |
AK; AB; BC; NT; YT; e Asia (Russian Far East, n Siberia) |
ID; MT; UT; WY
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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 globosa is an apomictic species closely related to D. burkei (M. D. Windham, unpubl.). Though often treated as a variety of D. densifolia, it is morphologically and phyletically distinct from that species. Both R. C. Rollins (1993) and N. H. Holmgren (2005b) indicated that the species occurs in Colorado, but we have not seen material for that state. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 7, p. 314. | FNA vol. 7, p. 308. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | D. hirta var. tenella, D. kananaskis, D. longipes | D. apiculata, D. densifolia var. apiculata, D. densifolia var. decipiens, D. densifolia var. globosa |
Name authority | Komarov: Repert. Spec. Nov. Regni Veg. 13: 167. (1914) | Payson: Amer. J. Bot. 4: 257. (1917) |
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