Draba monoensis |
Draba ramulosa |
|
---|---|---|
Mono Draba, White Mountains Draba |
Tushar Mountain Draba |
|
Habit | Perennials; (usually cespitose); caudex simple or branched (poorly developed, with persistent leaf remains); sometimes scapose. | Perennials; (loosely matted, grayish); caudex branched (with persistent leaf bases, branches creeping, sometimes terminating in sterile rosettes); not scapose. |
Stems | unbranched, (0.05–)0.1–0.4 dm, usually pubescent throughout, rarely sparsely pubescent or glabrous distally, trichomes simple and 2-rayed, (often crisped), 0.1–0.6 mm. |
unbranched, 0.4–0.6 dm, densely pubescent throughout, trichomes dendritic, 3–6-rayed, (often crisped), 0.1–0.4 mm. |
Basal leaves | rosulate; subsessile or shortly petiolate; petiole margin ciliate or not; blade narrowly oblanceolate, (0.3–)0.5–1.6(–2) cm × (1–)1.5–3(–4) mm, margins usually entire, rarely subapically denticulate, (ciliate or not), surfaces pubescent with simple and stalked, 2-rayed trichomes, 0.1–0.7 mm, (midvein obscure abaxially). |
(imbricate); not rosulate; sessile; blade obovate to oblanceolate, 0.4–1.1 cm × 2–3.2 mm, margins entire, (base and margins not ciliate), surfaces pubescent with stalked, 4–8-rayed trichomes, 0.1–0.5 mm, (sometimes 1 or more rays spurred), adaxially sometimes trichomes simple. |
Cauline leaves | 0–2 (or 3); sessile; blade ovate to oblong, margins entire, surfaces pubescent as basal. |
2 or 3 (sometimes basal leaves spaced, flowering stem appearing to 8-leaved); sessile; blade oblong to ovate, margins entire, surfaces pubescent as basal. |
Racemes | (3–)6–13(–17)-flowered, ebracteate or proximalmost 1 (or 2) flowers bracteate, not or slightly elongated in fruit; rachis not flexuous, usually pubescent as stem, rarely glabrous. |
4–15-flowered, ebracteate or proximalmost 1 or 2 flowers bracteate, slightly elongated in fruit; rachis not flexuous, pubescent as stem. |
Flowers | sepals (persistent), oblong, 1–1.5 mm, subapically sparsely pubescent, (trichomes simple); petals white, spatulate, 1.5–2 × 0.5–0.6 mm; anthers ovate, 0.15–0.2 mm. |
sepals broadly ovate, 1.7–2.4 mm, pubescent, (trichomes short-stalked, 2–5-rayed); petals yellow, obovate to oblanceolate, 3–4.5 × 1.5–2.5 mm; anthers ovate, 0.4–0.5 mm. |
Fruiting pedicels | divaricate-ascending, straight, 1–2.5(–4) mm, usually pubescent as stem, rarely glabrous. |
divaricate-ascending, usually straight, rarely curved upward, 3–6(–10) mm, pubescent, trichomes 3–6-rayed, (crisped, 0.1–0.4 mm), and, sometimes, simple. |
Fruits | ovoid to subellipsoid, plane, slightly inflated basally, (2–)3–5 × (1.2–)1.5–2.5 mm; valves usually puberulent, rarely glabrous, trichomes simple, 0.05–0.2 mm; ovules 12–20 per ovary; style 0.1–0.2 mm. |
(not appressed to rachis), ovate to elliptic, plane, flattened, 4–6.5 × 2.5–4 mm; valves densely pubescent, trichomes simple and short-stalked, 2–5-rayed, 0.08–0.35 mm; ovules 6–12 per ovary; style (0.1–)0.3–0.7 mm. |
Seeds | ovoid, 0.6–0.8 × 0.4–0.6 mm. |
oblong, 1.4–1.8 × 0.8–1.2 mm. |
Draba monoensis |
Draba ramulosa |
|
Phenology | Flowering Jul–Aug. | Flowering Jun–Aug. |
Habitat | Gravelly alpine meadows | Rock outcrops, talus, gravelly soils |
Elevation | 3600-4000 m (11800-13100 ft) | 3300-3600 m (10800-11800 ft) |
Distribution |
CA |
UT |
Discussion | Of conservation concern. Draba monoensis appears to be polyploid (M. D. Windham, unpubl.), and its morphological similarity to D. fladnizensis (R. C. Rollins 1993) may indicate that the latter is one of its progenitors. The species is known from the White Mountains of Mono County. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Of conservation concern. Molecular and chromosomal data (M. D. Windham, unpubl.) strongly suggest that Draba ramulosa is an allopolyploid species. It is thought to have originated through hybridization between D. sobolifera and a member of the white-flowered, euploid lineage of M. A. Beilstein and M. D. Windham (2003). It is easily distinguished from D. sobolifera by having pale yellow to whitish (versus bright yellow) petals, grayish (versus green) foliage, non-ciliate (versus ciliate) basal leaves pubescent with 4–8-rayed (versus 2–4-rayed) trichomes, often proximally bracteate (versus ebracteate) racemes, and flattened (versus inflated basally) fruits. Draba ramulosa is known from the Tushar Mountains in south-central Utah (Beaver and Piute counties). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 7, p. 320. | FNA vol. 7, p. 332. |
Parent taxa | ||
Sibling taxa | ||
Name authority | Rollins & R. A. Price: Aliso 12: 22, figs. 1f–j, 3. (1988) | Rollins: Contr. Gray Herb. 214: 6. (1984) |
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