Draba carnosula |
Draba arctogena |
|
---|---|---|
Mount Eddy Draba, Mt. Eddy Draba |
fellfield whitlowgrass |
|
Habit | Perennials; (loosely cespitose); caudex branched (somewhat surculose, with persistent leaf bases, branches sometimes terminating in sterile rosettes); scapose. | Perennials; (cespitose); caudex branched (sometimes with persistent leaf remains); sometimes scapose. |
Stems | unbranched, 0.3–1.2 dm, glabrous throughout. |
unbranched, 0.3–1.4 dm, pubescent throughout, trichomes simple, 0.2–1 mm, and 2–6-rayed, 0.05–0.3 mm. |
Basal leaves | rosulate; petiolate; petiole (persistent, midvein prominent), ciliate, (trichomes sparse, short-stalked, 2–4-rayed, sometimes with simple ones, 0.2–0.5 mm); blade (somewhat fleshy), oblanceolate or spatulate to obovate, 0.3–1.5 cm × 1.5–5 mm, margins entire, (pubescent as petiole), surfaces glabrous. |
rosulate; petiolate; petiole base and margin ciliate, (trichomes mostly simple, 0.2–1 mm); blade oblanceolate to narrowly obovate, 0.4–1.7 cm × 1.5–6 mm, margins entire or with 1–3 teeth on each side, surfaces pubescent with primarily simple trichomes, 0.3–1mm, abaxially mixed with stalked, 4–10-rayed ones, 0.1–0.2 mm. |
Cauline leaves | 0. |
0 or 1; sessile; blade ovate to oblong, margins entire or toothed, surfaces pubescent as basal. |
Racemes | 2–6-flowered, ebracteate, elongated in fruit; rachis not flexuous, glabrous. |
2–14(–17)-flowered, ebracteate, elongated in fruit; rachis not flexuous, pubescent as stem. |
Flowers | sepals ovate, 3–4 mm, glabrous; petals yellow, oblanceolate, 5–7 × 1.3–2 mm; anthers oblong, 0.7–0.9 mm. |
sepals ovate, 1.8–2.5 mm, pubescent, (trichomes simple and short-stalked, 2–4-rayed); petals white, spatulate, 3–4 × 1.5–2 mm; anthers ovate, 0.3–0.4 mm. |
Fruiting pedicels | divaricate-ascending, straight, 3–8 mm, usually glabrous, rarely trichomes simple. |
suberect to ascending, straight, 1–5(–7) mm, pubescent, trichomes simple and 2–4-rayed. |
Fruits | lanceolate to elliptic-lanceolate, plane, strongly flattened, 10–23 × 4–6 mm; valves (each with distinct midvein), glabrous; ovules 8–12 per ovary; style 2–3 mm. |
oblong, plane, flattened, 4–9 × 2–3.5 mm; valves pubescent, trichomes short-stalked, 2–4-rayed, 0.1–0.5 mm, sometimes with simple ones; ovules 20–32 per ovary; style 0.1–0.4 mm (stigma distinctly wider than style). |
Seeds | (broadly winged), orbicular, 3–4.5 in diam.; (wing 1–1.5 mm wide). |
ovoid, 0.7–1 × 0.5–0.6 mm. |
2n | = 48. |
|
Draba carnosula |
Draba arctogena |
|
Phenology | Flowering Jun–Jul. | Flowering Jun–Jul. |
Habitat | Open rocky hillsides | Scree, sandy hills, gravel flats |
Elevation | 2800-3100 m (9200-10200 ft) | 0-450 m (0-1500 ft) |
Distribution |
CA |
NT; NU; Greenland |
Discussion | Of conservation concern. Although Draba carnosula was reduced by Hitchcock to a variety of D. howellii, it differs significantly by having leafless flowering stems, 2–6-flowered racemes, and broadly winged seeds 3–4.5 mm in diam. Draba howellii almost always has 1–3-leaved stems, (5–)7–18(–25)-flowered racemes, and not winged, distally appendaged seeds 1–1.6 mm in diam. Draba carnosula is known only from a few collections from Mount Eddy in Trinity County and the north side of Mount Shasta in Siskiyou County. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Draba arctogena is sometimes confused with D. norvegica, from which it differs by having less elongated fruiting racemes, abaxial leaf surfaces with 4–10-rayed (versus cruciform or, rarely, 2–6-rayed) trichomes, and fruits with 2–4-rayed trichomes, 0.1–0.5 mm, (versus glabrous or with simple and 2–4-rayed trichomes, 0.05–0.25 mm). The limits of D. arctica, D. arctogena, D. cinerea, and D. oblongata need to be critically evaluated in light of molecular and cytological data. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 7, p. 299. | FNA vol. 7, p. 292. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | D. howellii var. carnosula | D. groenlandica var. arctogena, D. cinerea var. arctogena |
Name authority | O. E. Schulz: in H. G. A. Engler, Pflanzenr. 89[IV,105]: 82. (1927) | (E. Ekman) E. Ekman: Svensk Bot. Tidskr. 25: 492. (1932) |
Web links |