Draba ogilviensis |
Draba aurea |
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Ogilvie Range Draba |
golden Draba, golden Draba whitlow-grass, golden whitlow-grass, twisted-pod Draba |
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Habit | Perennials; (stoloniferous); caudex branched (sparsely covered with petiole remains, branches slender, creeping, loosely matted); often scapose. | Perennials; (not cespitose); caudex simple or branched; not scapose. |
Stems | unbranched, 0.4–1.5 dm, glabrous or pubescent throughout, trichomes simple and short-stalked, 2- or 3-rayed, 0.1–0.5 mm. |
sometimes branched distally, (0.5–) 1–3.5(–5.2) dm, pubescent throughout, trichomes simple (non-crisped), 0.4–1.3 mm, and 3–6-rayed ones, 0.1–0.5 mm. |
Basal leaves | not rosulate; (subopposite); petiolate; petiole base and margin ciliate or not, (trichomes simple, 0.2–0.8 mm); blade oblanceolate or lanceolate, 0.5–1.5 cm × 1.5–5 mm, margins entire, surfaces glabrous or sparsely pubescent with simple and stalked, 2–4-rayed trichomes, 0.1–0.5 mm, (midvein obscure abaxially). |
rosulate; petiolate; petiole (distinct or obscure) ciliate, (trichomes simple, to 0.8 mm); blade oblanceolate to obovate, (0.4–)1–3.7(–5) cm × (1–)2–7(–10) mm, margins entire or denticulate, surfaces pubescent, trichomes stalked, (2–)4–7 (or 8)-rayed, 0.2–0.5(–0.6) mm. |
Cauline leaves | (0 or) 1 or 2; (subopposite); sessile; blade ovate or oblong, margins entire, surfaces pubescent as basal. |
5–20(–26); sessile; blade oblong to lanceolate or ovate, margins entire or dentate, surfaces pubescent as basal, sometimes adaxially with simple trichomes. |
Racemes | 5–13-flowered, ebracteate, elongated in fruit; rachis not or slightly flexuous, glabrous or pubescent as stem. |
(10–)18–52(–72)-flowered, usually bracteate on proximalmost 1–12(–17) flowers, rarely ebracteate, elongated in fruit; rachis not flexuous, pubescent as stem. |
Flowers | sepals ovate, 2–3 mm, glabrous or pubescent, (trichomes simple); petals golden yellow, obovate, 3.5–6 × 2–3 mm; anthers ovate, 0.3–0.5 mm. |
sepals (green or yellowish), oblong, 2.2–3 mm, pubescent, (trichomes simple and branched); petals yellow, oblanceolate, 3.5–5 × 1.5–2.5 mm; anthers ovate, 0.4–0.5 mm. |
Fruiting pedicels | horizontal to divaricate, often curved upward, 6–13(–17) mm, glabrous or sparsely pubescent, trichomes simple and 2-rayed. |
divaricate-ascending to ascending or suberect, straight, 3–13(–20) mm, pubescent as stem. |
Fruits | oblong, plane, flattened, 6–9 × 2–3 mm; valves glabrous; ovules 8–20 per ovary; style 0.4–1 mm. |
(often subappressed to rachis), lanceolate to linear-lanceolate or narrowly oblong, slightly twisted or plane, flattened, (6–)9–14(–17) × 2–3.5 mm; valves pubescent, trichomes simple and short-stalked, 2–4-rayed, 0.05–0.3 mm; ovules 28–38(–44) per ovary; style 0.5–1.2(–1.5) mm. |
Seeds | ovoid, 0.9–1 × ca. 0.6 mm. |
oblong, 0.9–1.3 × 0.5–0.7 mm. |
2n | = 16. |
= 74. |
Draba ogilviensis |
Draba aurea |
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Phenology | Flowering Jun–Aug. | Flowering Jun–Aug. |
Habitat | Tundra, river flats and banks, exposed talus slopes, hummocks in wet sedge meadows | Rock outcrops, talus, damp gullies and meadows, subalpine conifer woodlands, alpine slopes and turf, tundra, road banks, river gravel |
Elevation | 900-2200 m (3000-7200 ft) | (0-)700-4200 m ((0-)2300-13800 ft) |
Distribution |
AK; NT; YT |
AK; AZ; CO; ID; MT; NM; NV; SD; UT; WA; WY; AB; BC; MB; NF; NT; NU; ON; QC; SK; YT; Greenland
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Discussion | The limits of Draba ogilviensis were confused by authors who reduced it to synonymy of D. juvenilis or D. sibirica. A thorough discussion of the three species and their distinguishing characteristics was provided by D. F. Murray and C. L. Parker (1999). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Draba aurea is extremely variable in plant size, number of cauline leaves, number of bracteate flowers, style length, and fruit size, shape, orientation, twisting, and indumentum. Much of the variation in the number of bracts, style length, fruit twisting, and growth habit occurs in Greenland, where the type specimen was collected and where the species is found near sea level. The highly deviant chromosome counts (e.g., 2n = 40 + 1, 64, 82) listed by R. C. Rollins (1993) and S. I. Warwick and I. A. Al-Shehbaz (2006) are mostly unvouchered and have to be disregarded; counts of 2n = ca. 80 have been re-assigned to Draba glabella. Published (G. A. Mulligan 2002) and unpublished counts made by Mulligan and M. D. Windham from Alaska, British Columbia, Colorado, Quebec, Utah, and Yukon indicate that the most common chromosome number of D. aurea is 2n = 74 (or 72). This suggests that the species is an allopolyploid (hexaploid or higher), incorporating genomes from both euploid and aneuploid lineages (M. A. Beilstein and Windham 2003). Detailed cytological and molecular studies are much needed to fully understand this widely distributed and highly variable species. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 7, p. 324. | FNA vol. 7, p. 294. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | D. aurea var. aureiformis, D. aurea var. leiocarpa, D. aurea var. luteola, D. aureiformis, D. aureiformis var. leiocarpa, D. bakeri, D. decumbens, D. henneana var. maccallae, D. luteola, D. luteola var. minganensis, D. maccallae, D. minganensis, D. surculifera, D. uber | |
Name authority | Hultén: Bot. Not. 119: 315, fig. 2. (1966) | Vahl ex Hornemann: Fors. Oecon. Plantel. ed. 2, 599. (1806) |
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