Draba brachycarpa |
Draba malpighiacea |
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short-pod whitlowgrass, shortfruit Draba, shortpod Draba |
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Habit | Annuals; not scapose. | Perennials; caudex simple or branched (sometimes with persistent leaf bases); not scapose. |
Stems | usually branched, rarely unbranched, (0.3–)0.4–1.9(–2.2) dm, pubescent throughout, trichomes sessile, cruciform, 0.2–0.6(–0.8) mm (rays often equal, or those parallel to stem axis longer). |
unbranched, 0.5–1.5 dm, pubescent throughout, trichomes malpighiaceous, 0.2–0.5 mm, and sometimes simple. |
Basal leaves | not rosulate; petiolate; petiole (to 0.5 cm), not ciliate; blade oblanceolate to obovate, 0.5–2 cm × 2–8 mm, margins entire, surfaces pubescent, trichomes cruciform, 0.2–0.6(–0.8) mm. |
rosulate; petiolate; petiole not ciliate; blade oblanceolate to spatulate, 0.5–1.8 cm × 2–4 mm, margins entire or dentate, (not ciliate proximally), surfaces pubescent with malpighiaceous trichomes, 0.3–0.6 mm. |
Cauline leaves | (4–)6–11; sessile; blade lanceolate to oblong or linear, margins entire, surfaces pubescent as basal. |
4–13; sessile; blade broadly ovate to lanceolate, margins denticulate, surfaces pubescent as basal. |
Racemes | (main branch) (20–)25–65(–74)-flowered, ebracteate, elongated in fruit; rachis not flexuous, pubescent as stem. |
10–33-flowered, ebracteate, elongated in fruit; rachis not flexuous, glabrous or pubescent, trichomes simple and/or malpighiaceous. |
Flowers | (late ones cleistogamous, apetalous); sepals (green or pink), oblong, 0.7–1.2(–1.5) mm, pubescent; petals white, spatulate, 2–3 × 0.8–1.1 mm; anthers ovate, 0.15–0.25 mm. |
sepals ovate, 2.5–3 mm, subapically pubescent, (trichomes simple and malpighiaceous); petals yellow, oblanceolate, 4–5 × 1.5–2 mm; anthers oblong, 0.7–1 mm. |
Fruiting pedicels | horizontal to divaricate-ascending, straight, (1–)1.5–4(–5) mm, pubescent, trichomes cruciform. |
divaricate-ascending, straight or curved upward, 6–13 mm, pubescent abaxially, trichomes simple and/or malpighiaceous. |
Fruits | usually elliptic to linear-elliptic, rarely ovate-elliptic, plane, flattened, (2–)2.5–5(–6) × 0.9–1.4(–1.9) mm; valves glabrous; ovules 8–16(–20) per ovary; style 0.05–0.1 mm. |
elliptic to elliptic-lanceolate, plane, flattened, 5–10 × 1.5–2.2 mm; valves glabrous; ovules 14–18 per ovary; style 0.8–1.2 mm. |
Seeds | (winged), ovoid, 0.5–0.7 × 0.4–0.5 mm. |
ovoid, 1–1.4 × 0.7–0.9 mm. |
2n | = 16. |
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Draba brachycarpa |
Draba malpighiacea |
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Phenology | Flowering Feb–May. | Flowering Jun–Aug. |
Habitat | Open woods, cedar glades, pastures and lawns, roadsides, disturbed sites | Rock outcrops and rocky slopes in subalpine conifer forests |
Elevation | 0-300 m (0-1000 ft) | 3000-3500 m (9800-11500 ft) |
Distribution |
AL; AR; AZ; FL; GA; IL; IN; KS; KY; LA; MO; MS; NC; OH; OK; OR; SC; TN; TX; VA
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CO |
Discussion | Draba brachycarpa is closely related to D. aprica and the two are sometimes confused. It is readily distinguished by having leaves with sessile (versus stalked) trichomes, glabrous (versus pubescent) fruits, and smaller (0.5–0.7 versus 0.9–1.1 mm) seeds. The records from Arizona and Oregon are based on old collections, Porter 802 (Devil’s Canyon, 22 Feb 1926, US) and Howell s.n. (near Cobarg, Willamette Valley, 7 Apr 1887, US); it is not known if these records represent introductions or remnants of a previously wider distribution. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Draba malpighiacea, which is restricted to higher elevations in Hinsdale, La Plata, and Montezuma counties, has been included within D. spectabilis by previous authors. Preliminary data suggest that it is one of the diploid parents of tetraploid D. spectabilis. It is readily distinguished from all species of Draba in Canada and the United States by having a leaf indumentum of exclusively malpighiaceous trichomes. The only other species in the flora area with such trichomes is D. sibirica, a stoloniferous, scapose perennial known only from Greenland. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 7, p. 296. | FNA vol. 7, p. 318. |
Parent taxa | Brassicaceae > tribe Arabideae > Draba | Brassicaceae > tribe Arabideae > Draba |
Sibling taxa | ||
Synonyms | Abdra brachycarpa | |
Name authority | Nuttall ex Torrey & A. Gray: Fl. N. Amer. 1: 108. (1838) | Windham & Al-Shehbaz: Harvard Pap. Bot. 12: 417. (2007) |
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