Draba praealta |
Draba incerta |
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Draba, tall Draba, tall whitlow-grass, tall whitlow-grass Draba |
whitlow-wort, Yellowstone Draba, Yellowstone Draba whitlow-wort, Yellowstone whitlow-grass, Yellowstone whitlow-wort |
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Habit | Annuals or perennials; (short-lived); caudex simple or branched; not scapose. | Perennials; (cespitose, often pulvinate); caudex branched (dense with persistent leaf remains, branches sometimes terminating in sterile rosettes); scapose. |
Stems | branched or unbranched, (0.5–)0.8–3.2(–3.8) dm, pubescent throughout, trichomes 3–5-rayed, 0.1–0.4 mm, with simple and 2-rayed ones, 0.4–1 mm. |
unbranched, (0.2–)0.4–1.4(–2.1) dm, often pubescent throughout, sometimes glabrous distally, trichomes often simple and 2–5-rayed, 0.1–0.5 mm, (sometimes with mostly subpectinate ones). |
Basal leaves | rosulate; subsessile; petiole base ciliate, (trichomes simple and 2-rayed, 0.2–0.8 mm); blade oblanceolate, (0.7–)1–3.5(–4.5) cm × 1.5–7(–9) mm, margins usually dentate, rarely entire, surfaces pubescent, abaxially with stalked, 3–6-rayed trichomes, 0.1–0.5 mm, adaxially with stalked, 3–5-rayed, 0.1–0.6 mm, and simple ones, to 0.8 mm. |
rosulate; petiolate; petiole (0–1 cm), ciliate throughout; blade narrowly oblanceolate to linear, (0.4–)0.6–1.7(–2.5) cm × (1–)1.5–3.5(–5) mm, margins entire, (ciliate, trichomes usually simple, rarely 2-rayed, 0.2–1.1 mm), surfaces usually pubescent with short-stalked, pectinate trichomes, 0.15–0.5 mm, sometimes also with 4–6-rayed ones, (midvein usually obscure abaxially), sometimes glabrous adaxially. |
Cauline leaves | (1 or) 2–5(–9); sessile; blade ovate to lanceolate, margins dentate or entire, surfaces pubescent as basal. |
usually 0 (or 1, as a bract); sessile; blade linear to oblong, margins entire, surfaces pubescent as basal. |
Racemes | (5–)8–30(–37)-flowered, ebracteate, elongated in fruit; rachis not flexuous, pubescent as stem. |
3–14(–30)-flowered, usually ebracteate, rarely proximalmost flowers bracteate, elongated in fruit; rachis not flexuous, glabrous or pubescent as stem. |
Flowers | (late-season ones petaliferous); sepals ovate, 1.7–2.5 mm, pubescent, (trichomes simple and stalked, 2-rayed); petals white, oblanceolate to spatulate, 2.8–3.5(–4) × 0.8–1.2 mm; anthers ovate, 0.2–0.3 mm. |
sepals broadly ovate, 2.5–3.5(–4) mm, pubescent, (trichomes simple and 2- or 3-rayed); petals yellow (fading white), oblanceolate to obovate, 4–6 × 1.5–2.5 mm; anthers ovate, 0.3–0.5 mm. |
Fruiting pedicels | divaricate-ascending to ascending or suberect (not appressed to rachis), straight, (3–)4–10(–12) mm, pubescent, trichomes 3–5-rayed (0.1–0.4 mm), and sometimes simple. |
ascending, straight, (2.5–)4–11(–27) mm, glabrous or pubescent, trichomes 2–5-rayed or pectinate. |
Fruits | (erect, not appressed to rachis) lanceolate to linear-lanceolate, plane, flattened, (5–)7–12(–15) × 1.5–2.5(–3) mm; valves puberulent, trichomes simple and short-stalked, 2–4-rayed, 0.05–0.25 mm; ovules (24–)30–52 per ovary; style 0.03–0.1(0.15) mm. |
broadly ovate to lanceolate, plane, flattened, 5–9(–11) × 2–4 mm; valves glabrous or puberulent, trichomes simple and 2-rayed, 0.05–0.3 mm; ovules 8–16(–20) per ovary; style 0.2–0.9 mm. |
Seeds | oblong, 0.8–1.1 × 0.5–0.6 mm, (often apiculate). |
oblong, 1.1–1.5 × 0.7–1 mm. |
2n | = 56. |
= 112. |
Draba praealta |
Draba incerta |
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Phenology | Flowering Jun–Aug. | Flowering Jun–Aug. |
Habitat | Rocky pine slopes, subalpine areas, alpine meadows, grassy volcanic ridges, woodlands, damp rocky areas, limestone talus, shale cliffs, steep hillsides | Rock outcrops, talus, gravelly areas, tundra |
Elevation | 1200-2900 m (3900-9500 ft) | 0-3300 m (0-10800 ft) |
Distribution |
CA; ID; MT; NV; OR; WA; WY; AB; BC; NT; YT; e Asia (Russian Far East [Chukchi Peninsula])
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AK; CO; ID; MT; NV; UT; WA; WY; AB; BC; QC; YT
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Discussion | Morphological and chromosomal evidence (M. D. Windham, unpubl.) suggests that Draba praealta may be an allopolyploid originating through hybridization between D. albertina and D. cana. Both R. C. Rollins (1993) and N. H. Holmgren (2005b) placed D. lonchocarpa var. dasycarpa in the synonymy of D. lonchocarpa. G. A. Mulligan (1974) indicated that the type of var. dasycarpa does not belong to that species and he correctly annotated its isotype (Macoun 64454, CAN) as D. praealta. Mulligan (1976) and Rollins indicated that D. praealta occurs in Alaska, but we have not seen unequivocal material from the state. We have not seen the material on which A. E. Katenin and V. V. Petrovsky (1995) based their record from the Russian Far East. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Draba incerta was shown by G. A. Mulligan (1972) to be sexually reproducing and 14-ploid with x = 8. It is often confused with the apomict D. oligosperma (2n = 32, 64). Draba incerta is readily separated from D. oligosperma by having well-formed (versus abortive) anthers and pollen, stalked (versus sessile) leaf trichomes, and ciliate (versus non-ciliate) basal leaves with obscure (versus prominent) midveins. Although both species have leafless scapes, one often finds a bract adnate to, or subtending, the proximalmost pedicel in D. incerta. Draba incerta is found near sea level in Alaska. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 7, p. 331. | FNA vol. 7, p. 313. |
Parent taxa | Brassicaceae > tribe Arabideae > Draba | Brassicaceae > tribe Arabideae > Draba |
Sibling taxa | ||
Synonyms | D. cascadensis, D. columbiana, D. dolichopoda, D. lapilutea, D. lonchocarpa var. dasycarpa, D. praealta var. yellowstonensis, D. yellowstonensis | D. exalata, D. incerta var. laevicapsula, D. incerta var. peasei, D. laevicapsula, D. peasei |
Name authority | Greene: Pittonia 3: 306. (1898) | Payson: Amer. J. Bot. 4: 261. (1917) |
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