Draba carnosula |
Draba aurea |
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Mount Eddy Draba, Mt. Eddy Draba |
golden Draba, golden Draba whitlow-grass, golden whitlow-grass, twisted-pod Draba |
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Habit | Perennials; (loosely cespitose); caudex branched (somewhat surculose, with persistent leaf bases, branches sometimes terminating in sterile rosettes); scapose. | Perennials; (not cespitose); caudex simple or branched; not scapose. |
Stems | unbranched, 0.3–1.2 dm, glabrous throughout. |
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 | rosulate; petiolate; petiole (persistent, midvein prominent), ciliate, (trichomes sparse, short-stalked, 2–4-rayed, sometimes with simple ones, 0.2–0.5 mm); blade (somewhat fleshy), oblanceolate or spatulate to obovate, 0.3–1.5 cm × 1.5–5 mm, margins entire, (pubescent as petiole), surfaces glabrous. |
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. |
5–20(–26); sessile; blade oblong to lanceolate or ovate, margins entire or dentate, surfaces pubescent as basal, sometimes adaxially with simple trichomes. |
Racemes | 2–6-flowered, ebracteate, elongated in fruit; rachis not flexuous, glabrous. |
(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, 3–4 mm, glabrous; petals yellow, oblanceolate, 5–7 × 1.3–2 mm; anthers oblong, 0.7–0.9 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 | divaricate-ascending, straight, 3–8 mm, usually glabrous, rarely trichomes simple. |
divaricate-ascending to ascending or suberect, straight, 3–13(–20) mm, pubescent as stem. |
Fruits | lanceolate to elliptic-lanceolate, plane, strongly flattened, 10–23 × 4–6 mm; valves (each with distinct midvein), glabrous; ovules 8–12 per ovary; style 2–3 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 | (broadly winged), orbicular, 3–4.5 in diam.; (wing 1–1.5 mm wide). |
oblong, 0.9–1.3 × 0.5–0.7 mm. |
2n | = 74. |
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Draba carnosula |
Draba aurea |
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Phenology | Flowering Jun–Jul. | Flowering Jun–Aug. |
Habitat | Open rocky hillsides | Rock outcrops, talus, damp gullies and meadows, subalpine conifer woodlands, alpine slopes and turf, tundra, road banks, river gravel |
Elevation | 2800-3100 m (9200-10200 ft) | (0-)700-4200 m ((0-)2300-13800 ft) |
Distribution |
CA |
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 | Of conservation concern. Although Draba carnosula was reduced by Hitchcock to a variety of D. howellii, it differs significantly by having leafless flowering stems, 2–6-flowered racemes, and broadly winged seeds 3–4.5 mm in diam. Draba howellii almost always has 1–3-leaved stems, (5–)7–18(–25)-flowered racemes, and not winged, distally appendaged seeds 1–1.6 mm in diam. Draba carnosula is known only from a few collections from Mount Eddy in Trinity County and the north side of Mount Shasta in Siskiyou County. (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. 299. | FNA vol. 7, p. 294. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | D. howellii var. carnosula | 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 | O. E. Schulz: in H. G. A. Engler, Pflanzenr. 89[IV,105]: 82. (1927) | Vahl ex Hornemann: Fors. Oecon. Plantel. ed. 2, 599. (1806) |
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