Draba glabella |
Draba mogollonica |
|
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golden Draba, rock whitlow-grass, smooth Draba, smooth whitlow-grass, smooth whitlow-mustard |
Mogollon Mountain Draba |
|
Habit | Perennials; (sometimes cespitose); caudex simple or branched; not scapose. | Annuals, biennials, or, rarely, perennials; (short-lived); not scapose. |
Stems | branched or unbranched, (0.4–)1–3.5(–4.7) dm, often pubescent throughout (sometimes sparsely so distally), sometimes glabrous, trichomes simple and 2-rayed, (non-crisped), 0.2–1 mm, or subsessile, stellate-pectinate, and 3–8-rayed, 0.1–0.3 mm. |
usually branched, (0.6–)1.2–2.8(–3.6) dm, pubescent proximally, glabrous distally, trichomes simple, 0.3–1.3 mm, and 2–4-rayed, 0.1–0.6 mm. |
Basal leaves | rosulate; petiolate; petiole ciliate, (trichomes simple, 0.1–0.8 mm); blade oblanceolate to spatulate or linear-oblanceolate, (0.6–)1–3.5(–5) cm × 2–8(–10) mm, margins dentate or denticulate, (pubescent as petiole), surfaces pubescent with non-crisped, minutely stalked, 4–8(–12)-rayed, stellate-pectinate trichomes, 0.15–0.6 mm, (midvein obscure abaxially), adaxially sometimes also with simple trichomes, or glabrous. |
rosulate; petiole (0–2 cm), densely pubescent, (trichomes simple and 2–4-rayed, not ciliate); blade spatulate to obovate or oblanceolate, (1.5–)3–8(–10) cm × 7–25(–33) mm, margins dentate to denticulate, surfaces pubescent with long-stalked, cruciform, and fewer 2- or 3-rayed trichomes, 0.1–0.6 mm. |
Cauline leaves | 2–17(–25); sessile; blade ovate to oblong, margins dentate to subentire, surfaces often pubescent as basal, or predominantly with simple trichomes adaxially. |
1–3; sessile; blade oblong to ovate, margins entire, surfaces pubescent as basal. |
Racemes | (5–)8–26(–34)-flowered, ebracteate or proximalmost 1 or 2 flowers bracteate, elongated in fruit; rachis not flexuous, usually glabrous, rarely pubescent as stem. |
12–40(–51)-flowered, ebracteate, elongated in fruit; rachis not flexuous, usually glabrous, rarely proximally with relatively few trichomes. |
Flowers | sepals oblong, 2–3.5 mm, pubescent, (trichomes simple and short-stalked, 2–4-rayed); petals white, broadly obovate, 4–5.5 × 1.5–3 mm; anthers ovate, 0.3–0.5 mm. |
sepals oblong, 2.5–3.5 mm, sparsely pubescent, (trichomes simple and 2–4-rayed); petals yellow, spatulate, (5–)6–8.5 × 2.2–3.5 mm; anthers oblong, 0.7–0.9 mm. |
Fruiting pedicels | divaricate-ascending to suberect, straight, (1–)3–10(–16) mm, glabrous or pubescent as stem. |
horizontal to divaricate, straight, (6–)9–18(–22) mm, usually glabrous, rarely sparsely pubescent as stem proximally. |
Fruits | oblong to ovate or ovoid to lanceolate or linear-lanceolate, usually plane, rarely slightly twisted, flattened or inflated, (3–)5–12(–16) × 2–3.5 mm; valves glabrous or pubescent, trichomes simple or 2–4-rayed, 0.05–0.2(–0.4) mm; ovules (20–)24–36 per ovary; style 0.05–0.2(–0.5) mm. |
linear-elliptic to elliptic-lanceolate, slightly twisted, flattened, 6–19 × 2.5–3.5 mm; valves glabrous or pubescent, trichomes simple and short-stalked, 2(–4)-rayed, 0.07–0.3 mm; ovules 24–36 per ovary; style (0.8–)1–2.2 mm. |
Seeds | oblong, 0.9–1.1 × 0.5–0.7 mm. |
oblong, 1–1.4 × 0.7–0.8 mm. |
2n | = 64, 80. |
= 22. |
Draba glabella |
Draba mogollonica |
|
Phenology | Flowering May–Aug. | Flowering Apr–May. |
Habitat | Rock outcrops, talus, rocky ridges and knolls, meadows, tundra, gravelly beaches sandy river margins, disturbed soils | Rock outcrops and rocky slopes in oak-pine woodlands and mixed conifer communities |
Elevation | 0-1400 m (0-4600 ft) | 1500-2300 m (4900-7500 ft) |
Distribution |
AK; ME; VT; WI; BC; MB; NB; NL; NS; NT; NU; ON; QC; YT; Greenland; n Europe (n Russia); e Asia (Russian Far East, Siberia) |
AZ; NM |
Discussion | Draba glabella was reported by J. V. Freudenstein and J. K. Marr (1986) from Michigan, but that record likely was based on plants of D. arabisans, a highly variable species that occurs in that state. Draba glabella is extremely variable in indumentum, number of cauline leaves, fruiting pedicel length, fruit shape and size, style length, and seed number. M. L. Fernald (1934) divided it into five species and three varieties; R. C. Rollins (1993) recognized three species. Of these, G. A. Mulligan (1970, 1976) reduced D. laurentiana to synonymy of D. glabella and treated D. pycnosperma as a variety. Of all the segregates of D. glabella, var. pycnosperma might merit recognition. It is restricted to northwestern Newfoundland and northeastern Quebec, where var. glabella also grows. The main difference between the two varieties is the presence in var. pycnosperma of plump (versus flattened), ovoid to oblong fruits. Draba sornborgeri, recognized by Rollins as a distinct species, is merely a glabrescent form of D. glabella. Because of the tremendous morphological variability, wide distribution, extensive synonymy, and different chromosome numbers, D. glabella will require extensive molecular, cytological, and morphological studies to properly delimit the species and any potential infraspecific taxa. Some forms of Draba glabella approach both D. borealis and D. praealta, but these can be distinguished by examining the trichomes on the abaxial surfaces of basal leaf blades. In D. glabella, these trichomes are minutely stalked or subsessile and have branched rays. In the other two species, the trichomes have long stalks and the rays are always unbranched. The Linnaean name Draba hirta was applied to this species previously, and still is in Russia. The name is not typified, and the material at LINN is in bad condition and probably belongs to two species, D. glabella and D. norvegica, as recognized here. A typification of D. hirta may necessitate its re-introduction for this species. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Draba mogollonica is distributed in New Mexico primarily in the Mogollon and neighboring mountains in Catron, Grant, Sierra, and Socorro counties. It is reported herein for the first time from Arizona from Greenlee County, based on Barneby 2297 (NY), Rollins & Rollins 93113 (CAS, GH), and Windham 2918 (MO, UT). The only published chromosome count (n = 16, compiled in S. I. Warwick and I. A. Al-Shehbaz 2006) is erroneous; counts by M. D. Windham (unpubl.) from five populations representing all of the above-mentioned counties in Arizona and New Mexico consistently agree on n = 11. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 7, p. 307. | FNA vol. 7, p. 320. |
Parent taxa | Brassicaceae > tribe Arabideae > Draba | Brassicaceae > tribe Arabideae > Draba |
Sibling taxa | ||
Synonyms | D. arabisans var. canadensis, D. arabisans var. orthocarpa, D. canadensis, D. canadensis var. pycnosperma, D. daurica, D. glabella var. megasperma, D. glabella var. orthocarpa, D. glabella var. pycnosperma, D. henneana, D. hirta var. laurentiana, D. hirta var. pycnosperma, D. laurentiana, D. megasperma, D. norvegica var. pleiophylla, D. pycnosperma, D. sornborgeri | |
Name authority | Pursh: Fl. Amer. Sept. 2: 434. (1813) | Greene: Bot. Gaz. 6: 157. (1881) |
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