Draba brachycarpa |
Draba incana |
|
---|---|---|
short-pod whitlowgrass, shortfruit Draba, shortpod Draba |
twisted Draba |
|
Habit | Annuals; not scapose. | Biennials; 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). |
usually branched, rarely unbranched, (0.3–)0.6–3(–4) dm, densely pubescent proximally, trichomes simple, 0.4–1.3 mm, with fewer 2–4-rayed ones, to 0.3 mm, (distally with mostly branched trichomes, with fewer, simple ones). |
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 base and margin ciliate, (trichomes simple, 0.2–0.7 mm); blade lanceolate or oblanceolate to spatulate, 0.5–2.9 cm × 1–5(–9) mm, margins dentate, surfaces pubescent, abaxially with stalked, cruciform, or 2- or 3-rayed trichomes, 0.1–0.4 mm, (rarely with a branched ray), adaxially with simple trichomes, 0.1–0.7 mm, and stalked, 2–4-rayed ones. |
Cauline leaves | (4–)6–11; sessile; blade lanceolate to oblong or linear, margins entire, surfaces pubescent as basal. |
(15–)22–54(–76), (densely imbricate at least basally); sessile; blade ovate to oblong or lanceolate (base often densely bearded abaxially, trichomes simple, to 1.3 mm), margins dentate, surfaces pubescent as basal. |
Racemes | (main branch) (20–)25–65(–74)-flowered, ebracteate, elongated in fruit; rachis not flexuous, pubescent as stem. |
(11–)17–36(–48)-flowered, bracteate basally, elongated or not in fruit; rachis not flexuous, pubescent as stems distally. |
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, 2–2.5 mm, pubescent, (trichomes simple and short-stalked, 2–4-rayed); petals white, spatulate, 3.5–4.5 × 1–2 mm; anthers ovate, 0.3–0.4 mm. |
Fruiting pedicels | horizontal to divaricate-ascending, straight, (1–)1.5–4(–5) mm, pubescent, trichomes cruciform. |
erect to ascending, (subappressed to rachis), straight, (1.5–)2.5–6(–13) mm, pubescent, trichomes 2–4-rayed and simple. |
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. |
oblong to linear-lanceolate or elliptic, slightly twisted or plane, flattened, 5–10(–12) × 1.5–2.5(–3) mm; valves glabrous or pubescent, trichomes simple and short-stalked, 2–4-rayed, 0.05–0.3 mm; ovules (24–)30–40 per ovary; style 0.01–0.25 mm. |
Seeds | (winged), ovoid, 0.5–0.7 × 0.4–0.5 mm. |
oblong, 0.7–1.1 × 0.5–0.6 mm. |
2n | = 16. |
= 32. |
Draba brachycarpa |
Draba incana |
|
Phenology | Flowering Feb–May. | Flowering Jul–Aug. |
Habitat | Open woods, cedar glades, pastures and lawns, roadsides, disturbed sites | Rock outcrops, talus, gravelly shores |
Elevation | 0-300 m (0-1000 ft) | 0-200 m (0-700 ft) |
Distribution |
AL; AR; AZ; FL; GA; IL; IN; KS; KY; LA; MO; MS; NC; OH; OK; OR; SC; TN; TX; VA
|
MI; MN; MB; NB; NL; ON; PE; QC; Greenland; n Europe; c Europe (Russia) |
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.) |
|
Source | FNA vol. 7, p. 296. | FNA vol. 7, p. 312. |
Parent taxa | Brassicaceae > tribe Arabideae > Draba | Brassicaceae > tribe Arabideae > Draba |
Sibling taxa | ||
Synonyms | Abdra brachycarpa | D. confusa, D. contorta, D. incana subsp. confusa, D. incana var. confusa, D. incana var. contorta |
Name authority | Nuttall ex Torrey & A. Gray: Fl. N. Amer. 1: 108. (1838) | Linnaeus: Sp. Pl. 2: 643. (1753) |
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