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Brewer's whitlow grass, cushion Draba

Siberian whitlowgrass

Habit Perennials; (cespitose, grayish pubescent); caudex branched (sometimes covered with persistent leaf bases, branches short, compact); sometimes scapose. Perennials; (stoloniferous); caudex branched (sparsely covered with persistent petiole remains, branches slender, creeping); scapose.
Stems

unbranched, (0.1–)0.2–1(–1.5) dm, pubescent throughout, trichomes stalked, 4–10-rayed, 0.1–0.3 mm.

(subdecumbent when sterile), unbranched, 0.5–2.5 dm, sparsely to densely hispid, trichomes malpighiaceous, (flowering scapes sparsely pilose proximally with simple trichomes, often glabrous on distal 1/2).

Basal leaves

rosulate; petiolate;

petiole base ciliate, margin not ciliate, (trichomes simple and 2-rayed, 0.3–0.8 mm);

blade oblanceolate to obovate, (0.3–)0.4–1.5(–2.5) cm × 1.5–3(–5) mm, margins usually entire, rarely dentate, surfaces densely pubescent with stalked, 4–10-rayed, stellate trichomes, 0.1–0.2 mm (sometimes 1 or more rays spurred).

rosulate; petiolate;

blade oblong-lanceolate or oblanceolate, 0.4–2.2 cm × 1–5(–10) mm, margins entire, surfaces often pubescent, sometimes glabrous (except margins), with appressed, malpighiaceous trichomes (these sometimes with 1 or 2 shorter, lateral branches, appearing 3-fid or cross-shaped).

Cauline leaves

0–3(–6);

sessile;

blade oblong or lanceolate to ovate, margins entire (sometimes ciliate at base), surfaces usually pubescent as basal.

0.

Racemes

(5–)7–18(–24)-flowered, ebracteate, slightly to considerably elongated in fruit;

rachis not flexuous, pubescent with stalked, 4–10-rayed trichomes, (0.1–0.3 mm).

7–20-flowered, ebracteate, considerably elongated in fruit;

rachis not flexuous (straight), glabrous.

Flowers

sepals (persistent), ovate, 1.2–2 mm, pubescent, (trichomes short-stalked, 2–6-rayed);

petals white, spatulate to oblanceolate, 2–3 × 0.7–1.1 mm;

anthers ovate, 0.2–0.25 mm.

sepals (erect), oblong or ovate, 2–2.7 mm (lateral pair subsaccate basally), glabrous or abaxially sparsely pilose, (trichomes simple);

petals yellow, narrowly obovate, 4–6 × 2–3 mm, (apex emarginate);

anthers ovate-subcordate, 0.4–0.5 mm.

Fruiting pedicels

ascending, (sometimes slightly appressed to rachis), straight, 1.5–3(–4) mm, pubescent as rachis.

divaricate, straight or curved, (often filiform), 5–18(–23) mm, glabrous.

Fruits

lanceolate or oblong to linear, usually slightly to strongly twisted, rarely plane, flattened, 3.5–9(–11) × 1.5–2.5 mm;

valves pubescent, trichomes short-stalked, 2–5-rayed, 0.05–0.25 mm;

ovules 28–40 per ovary;

style 0.1–0.3(–0.4) mm.

usually oblong to elliptic, rarely sublinear, plane, flattened, 4–8 × 1.5–2.2 mm;

valves glabrous, (obscurely veined);

ovules 24–30 per ovary;

style 0.5–1 mm.

Seeds

ovoid, 0.5–0.7 × 0.3–0.5 mm.

(brown), ovoid, 0.9–1.2 × 0.5–0.6 mm.

2n

= 32.

= 16.

Draba breweri

Draba sibirica

Phenology Flowering Jul–Aug. Flowering May–Jul.
Habitat Rock outcrops, talus, exposed ridges, alpine areas Wet places on rocky slopes
Elevation 3100-4100 m (10200-13500 ft) 0-300 m (0-1000 ft)
Distribution
from FNA
CA
[WildflowerSearch map]
[BONAP county map]
from USDA
Greenland; Europe (Russia); Asia (Caucasus, Iran, Russian Far East, Siberia, Turkey, central republics)
[BONAP county map]
Discussion

The circumscription of Draba breweri was expanded by R. C. Rollins (1993) to include D. cana. Plants of D. cana differ from those of D. breweri by being non-cespitose (versus cespitose) and taller [(4–)10–30(–38) versus (1–)2–9(–15) cm], and by having basally bracteate (versus ebracteate) racemes, and stems, pedicels, and sepals pubescent with a mixture of simple and branched (versus exclusively branched) trichomes. Draba breweri is known to us from Alpine, Fresno, Inyo, Mono, Plumas, Tulare, and Tuolumne counties.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Draba sibirica is one of three species of the genus in North America exhibiting malpighiaceous trichomes. It is easily distinguished from others (D. malpighiacea and some plants of D. spectabilis) by a complete absence of cauline leaves. It is found in the flora area in northeastern Greenland.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Source FNA vol. 7, p. 297. FNA vol. 7, p. 337.
Parent taxa Brassicaceae > tribe Arabideae > Draba Brassicaceae > tribe Arabideae > Draba
Sibling taxa
D. abajoensis, D. albertina, D. aleutica, D. alpina, D. aprica, D. arabisans, D. arctica, D. arctogena, D. argyrea, D. arida, D. asprella, D. asterophora, D. aurea, D. aureola, D. bifurcata, D. borealis, D. brachycarpa, D. brachystylis, D. burkei, D. californica, D. cana, D. carnosula, D. chamissonis, D. cinerea, D. corrugata, D. corymbosa, D. crassa, D. crassifolia, D. cruciata, D. cuneifolia, D. cusickii, D. cyclomorpha, D. daviesiae, D. densifolia, D. exunguiculata, D. fladnizensis, D. glabella, D. globosa, D. graminea, D. grandis, D. grayana, D. heilii, D. helleriana, D. hitchcockii, D. howellii, D. incana, D. incerta, D. incrassata, D. inexpectata, D. jaegeri, D. juvenilis, D. kassii, D. kluanei, D. lactea, D. lemmonii, D. lonchocarpa, D. longisquamosa, D. macounii, D. maguirei, D. malpighiacea, D. micropetala, D. mogollonica, D. monoensis, D. mulliganii, D. murrayi, D. nemorosa, D. nivalis, D. norvegica, D. novolympica, D. oblongata, D. ogilviensis, D. oligosperma, D. oreibata, D. oxycarpa, D. palanderiana, D. pauciflora, D. paucifructa, D. paysonii, D. pectinipila, D. pedicellata, D. pennellii, D. petrophila, D. pilosa, D. platycarpa, D. porsildii, D. praealta, D. pterosperma, D. ramosissima, D. ramulosa, D. rectifructa, D. reptans, D. ruaxes, D. santaquinensis, D. saxosa, D. scotteri, D. serpentina, D. sharsmithii, D. sibirica, D. sierrae, D. simmonsii, D. smithii, D. sobolifera, D. spectabilis, D. sphaerocarpa, D. sphaeroides, D. standleyi, D. stenoloba, D. stenopetala, D. streptobrachia, D. streptocarpa, D. subalpina, D. subcapitata, D. subumbellata, D. trichocarpa, D. ventosa, D. verna, D. viridis, D. weberi, D. yukonensis, D. zionensis
D. abajoensis, D. albertina, D. aleutica, D. alpina, D. aprica, D. arabisans, D. arctica, D. arctogena, D. argyrea, D. arida, D. asprella, D. asterophora, D. aurea, D. aureola, D. bifurcata, D. borealis, D. brachycarpa, D. brachystylis, D. breweri, D. burkei, D. californica, D. cana, D. carnosula, D. chamissonis, D. cinerea, D. corrugata, D. corymbosa, D. crassa, D. crassifolia, D. cruciata, D. cuneifolia, D. cusickii, D. cyclomorpha, D. daviesiae, D. densifolia, D. exunguiculata, D. fladnizensis, D. glabella, D. globosa, D. graminea, D. grandis, D. grayana, D. heilii, D. helleriana, D. hitchcockii, D. howellii, D. incana, D. incerta, D. incrassata, D. inexpectata, D. jaegeri, D. juvenilis, D. kassii, D. kluanei, D. lactea, D. lemmonii, D. lonchocarpa, D. longisquamosa, D. macounii, D. maguirei, D. malpighiacea, D. micropetala, D. mogollonica, D. monoensis, D. mulliganii, D. murrayi, D. nemorosa, D. nivalis, D. norvegica, D. novolympica, D. oblongata, D. ogilviensis, D. oligosperma, D. oreibata, D. oxycarpa, D. palanderiana, D. pauciflora, D. paucifructa, D. paysonii, D. pectinipila, D. pedicellata, D. pennellii, D. petrophila, D. pilosa, D. platycarpa, D. porsildii, D. praealta, D. pterosperma, D. ramosissima, D. ramulosa, D. rectifructa, D. reptans, D. ruaxes, D. santaquinensis, D. saxosa, D. scotteri, D. serpentina, D. sharsmithii, D. sierrae, D. simmonsii, D. smithii, D. sobolifera, D. spectabilis, D. sphaerocarpa, D. sphaeroides, D. standleyi, D. stenoloba, D. stenopetala, D. streptobrachia, D. streptocarpa, D. subalpina, D. subcapitata, D. subumbellata, D. trichocarpa, D. ventosa, D. verna, D. viridis, D. weberi, D. yukonensis, D. zionensis
Synonyms D. breweri var. sublaxa Lepidium sibiricum, D. gmelinii, D. repens, D. sibirica subsp. arctica
Name authority S. Watson: Proc. Amer. Acad. Arts 23: 260. (1888) (Pallas) Thellung: Neue Denkschr. Schweiz. Naturf. Ges. 41: 318. (1907)
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