Draba grandis |
Draba arabisans |
|
---|---|---|
north Pacific Draba |
rock Draba, rock whitlow-mustard |
|
Habit | Perennials; caudex simple or branched (fleshy, with persistent leaf bases); not scapose. | Perennials; (sometimes cespitose); caudex simple or branched; not scapose. |
Stems | (decumbent), unbranched, (0.2–)0.5–2.7(–3.7) dm, pubescent throughout, trichomes 2–4-rayed, 0.05–0.2 mm. |
branched or unbranched, (0.5–)0.7–3(–4.5) dm, pubescent proximally, glabrous or pubescent distally, trichomes sessile (non-crisped), 4- or 5-rayed, stellate, or subpectinate, 0.07–0.4 mm. |
Basal leaves | rosulate; long-petiolate; petiole (winged, (1–)4–15 cm), often not ciliate (or ciliate to blade apex, trichomes simple, 0.3–0.8 mm); blade (somewhat fleshy), oblanceolate to spatulate or obovate, (1–)2–11(–17) cm × (5–)8–30(–45) mm, margins often coarsely dentate, (pubescent as petiole), surfaces usually pubescent, abaxially with stalked, 2–4-rayed trichomes, 0.05–0.25 mm, adaxially similar, or also with simple and long-stalked, 2-rayed trichomes, to 0.8 mm, rarely glabrescent, with mostly simple and 2-rayed trichomes. |
rosulate; petiolate; petiole base and margin sparsely ciliate, (trichomes simple and 2-rayed, 0.2–0.8 mm); blade oblanceolate to spatulate or linear-oblanceolate, 1–3.8(–5) cm × 2–5(–8) mm, margins dentate or denticulate, surfaces pubescent with sessile, non-crisped, 4- or 5-rayed, stellate trichomes, 0.07–0.5mm, (some rays branched, appearing 2–12-rayed, midvein obscure abaxially). |
Cauline leaves | 2–12(–16); sessile or petiolate; blade oblanceolate to obovate, margins dentate or entire, surfaces pubescent as basal. |
(2 or) 3–10(–13); sessile; blade ovate to oblong, margins dentate to subentire, surfaces pubescent as basal. |
Racemes | 5–26(–32)-flowered, ebracteate, elongated in fruit; rachis not flexuous, pubescent as stem. |
5–18(–25)-flowered, ebracteate, elongated in fruit; rachis not flexuous, glabrous or pubescent as stem. |
Flowers | sepals broadly ovate, 3–4 mm, pubescent, (trichomes simple and short-stalked, 2-rayed); petals yellow, oblanceolate to spatulate, 4.5–7 × 1.8–3 mm; anthers oblong, 0.7–1 mm. |
sepals oblong, 1.7–2.5 mm, pubescent, trichomes short-stalked, 3- or 4-rayed; petals white, broadly obovate, 3.5–5 × 1.5–2.5 mm; anthers ovate, 0.4–0.5 mm. |
Fruiting pedicels | horizontal to divaricate-ascending or ascending, usually straight, rarely curved upward, (5–)10–22(–27) mm, pubescent, trichomes 2–4-rayed (0.05–0.3 mm), sometimes with simple and spurred ones. |
divaricate-ascending to suberect, straight or slightly curved, (3–)4–10(–13) mm, glabrous or pubescent as stem. |
Fruits | oblong to lanceolate, or ovate to suborbicular, slightly twisted or plane, flattened, (6–)10–20(–25) × 4–7(–9) mm; valves glabrous; ovules 24–52 per ovary; style (0.2–)0.4–1.6(–2) mm. |
ovate to lanceolate or linear-lanceolate, usually slightly twisted, rarely plane, flattened, 5–11(–14) × 2–3.5 mm; valves usually glabrous, rarely pubescent, trichomes 3- or 4-rayed, 0.07–0.2 mm; ovules 20–28(–32) per ovary; style (0.2–)0.4–1 mm. |
Seeds | ovoid, 1.4–2 × 0.8–1.2 mm. |
oblong, 0.8–1.1 × 0.6–0.8 mm. |
2n | = 36. |
= 96. |
Draba grandis |
Draba arabisans |
|
Phenology | Flowering May–Jul. | Flowering Jun–Aug. |
Habitat | Rocky bluffs above salt-water beaches, loamy seaside banks, sea bird rookeries, coastal herbaceous tundra and sandy blowouts | Rock outcrops and talus (usually limestone or dolomite), open woods, rocky shores |
Elevation | 0-50(-200) m (0-200(-700) ft) | 0-300 m (0-1000 ft) |
Distribution |
AK; BC; e Asia (Kuril and Ratmanov islands, Russian Far East) |
ME; MI; MN; NY; VT; WI; MB; NB; NF; NS; ON; QC
|
Discussion | Almost all recent North American authors have used the name Draba hyperborea for this species. A. N. Berkutenko (1995) clearly showed that the type of that name belongs to an entirely different species that she placed in the genus Schivereckia Andrzejowski ex de Candolle. Draba grandis thus becomes the correct name for the North American taxon. Except for its fleshy leaves, Nesodraba is indistinguishable morphologically and molecularly from other species of Draba. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Draba arabisans is often confused with D. glabella (2n = 80); it is easily distinguished by having sessile (versus short-stalked) stellate trichomes on abaxial leaf blade surfaces and longer styles (0.2–)0.4–1 [versus 0.1–0.2(–0.4)] mm. Both species have twisted and plane fruits; D. arabisans has mostly twisted fruits; D. glabella has predominantly plane fruits. The complete absence of simple trichomes proximally on stems of D. arabisans can be a useful feature separating it from D. glabella, which often has at least some simple trichomes on the proximal half of the stem. Draba arabis Persoon is an illegitimate name, sometimes found in synonymy with D. arabisans. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 7, p. 309. | FNA vol. 7, p. 291. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | Cochlearia siliquosa, Cochlearia spathulata, D. greenei, D. hatchiae, D. hyperborea var. spathulata, D. spathulata, Nesodraba grandis, Nesodraba megalocarpa, Nesodraba siliquosa | D. arabisans var. superiorensis, D. incana var. arabisans, D. incana var. glabriuscula |
Name authority | Langsdorff ex de Candolle: Syst. Nat. 2: 355. (1821) | Michaux: Fl. Bor.-Amer. 2: 28. (1803) |
Web links |
|