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Rocky Mountain Draba

woodland Draba, woodland whitlow-grass, woods Draba, woods whitlow-grass, yellow whitlow-grass

Habit Perennials; (cespitose); caudex simple or branched (with persistent leaf bases); not scapose. Annuals; not scapose.
Stems

unbranched, 0.1–0.5(–0.8) dm, usually pubescent throughout, rarely glabrous, trichomes simple or subsessile, 2-rayed or spurred, (crisped), 0.1–0.5 mm.

unbranched or branched proximally, (0.3–)0.6–4.5(–6) dm, densely pubescent proximally, glabrous distally, trichomes simple, 0.5–1.3 mm, and stalked, 2–4-rayed, 0.1–0.5 mm.

Basal leaves

rosulate; petiolate;

petiole ciliate, (trichomes usually straight and simple, rarely also 2-rayed, 0.2–0.6(–0.8) mm);

blade linear to linear-oblanceolate, (0.5–)1–4 cm × 0.3–2(–3) mm, margins entire (pubescent as petiole), surfaces glabrous.

rosulate or not, petiolate;

petiole ciliate throughout;

blade oblong-obovate or oblanceolate, (0.4–)1–3.5(–5) cm × (2–)5–15(–20) mm, margins usually dentate to denticulate, rarely subentire, surfaces sparsely to densely pubescent with stalked, 2- or 3-rayed, and cruciform trichomes, 0.1–0.5 mm.

Cauline leaves

(1–)3–9(–12) (as bracts);

sessile;

blade linear to oblanceolate or lanceolate, margins entire, (ciliate proximally, similar to basal).

4–12(–15);

sessile;

blade broadly ovate to oblong, margins dentate or denticulate, surfaces pubescent, abaxially as basal, adaxially with primarily simple, and 2- or 3-rayed trichomes.

Racemes

3–15-flowered, bracteate, elongated in fruit;

rachis not flexuous, usually pubescent as stem, rarely glabrous.

(10–)18–60(–92)-flowered, ebracteate, considerably elongated in fruit;

rachis not flexuous (straight), glabrous.

Flowers

sepals ovate, 1.5–2.5 mm, glabrous or pubescent, (trichomes simple and short-stalked, 2-rayed);

petals yellow, spatulate to obovate, 3–5 × 1.5–3 mm;

anthers ovate, 0.3–0.5 mm.

sepals ovate, (0.7–)0.9–1.6 mm, sparsely pubescent, (trichomes simple);

petals yellow, spatulate to oblanceolate, (1.2–)1.7–2.2(–2.5) × (0.4–)0.6–1 mm, (deeply notched);

anthers broadly ovate to subreniform, 0.1–0.2 mm.

Fruiting pedicels

divaricate-ascending, usually straight, rarely curved upward, 3–10(–15) mm, usually pubescent as stem, rarely glabrous.

divaricate, straight, 7–28(–35) mm [(1.5–)2–7 times longer than fruit], glabrous.

Fruits

ovate-elliptic to lanceolate, slightly twisted or plane, flattened, 5–11 × 2.5–5 mm;

valves glabrous;

ovules 8–16 per ovary;

style 0.2–0.7 mm.

oblong to elliptic or, rarely, oblong-oblanceolate, plane, slightly flattened, (3–)5–8 (–10) × 1.5–2.5 mm;

valves glabrous or puberulent, trichomes simple, antrorse, 0.05–0.2 mm;

ovules (30–)36–60(–72) per ovary;

style 0.01–0.1 mm.

Seeds

ovoid, 1.2–1.5 × 0.7–1 mm.

ovoid, 0.5–0.7(–0.8) × 0.3–0.4(–0.5) mm.

2n

= 18.

= 16.

Draba graminea

Draba nemorosa

Phenology Flowering Jul–Sep. Flowering Apr–Jul.
Habitat Rocky areas and ridges, alpine tundra, gravel bars in streams Rock outcrops, open wooded slopes, meadows and prairies, stream banks, roadsides, disturbed gravelly grounds, waste places
Elevation 3000-4100 m (9800-13500 ft) 0-2700 m (0-8900 ft)
Distribution
from FNA
CO
[WildflowerSearch map]
[BONAP county map]
from FNA
AK; CA; CO; IA; ID; MI; MN; MT; ND; NE; NV; OR; SD; UT; WA; WI; WY; AB; BC; MB; NT; NU; ON; QC; SK; YT; Europe; Asia [Introduced in North America; introduced also in Australia]
[WildflowerSearch map]
[BONAP county map]
Discussion

Of conservation concern.

Draba graminea is occasionally confused with D. crassa, which occupies similar habitats and elevations. It is easily distinguished from the latter by having narrower [0.3–2(–3) versus 2.5–8(–10) mm wide] basal leaves and bracteate (versus ebracteate) racemes. It is known to us only from Hinsdale, La Plata, Ouray, San Juan, and San Miguel counties.

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

Source FNA vol. 7, p. 309. FNA vol. 7, p. 321.
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. 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. 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. 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
Synonyms Braya graminea, D. chrysantha var. graminea, D. chrysantha var. hirticaulis D. dictyota, D. nemoralis, D. nemorosa var. brevisilicula, D. nemorosa var. hebecarpa, D. nemorosa var. leiocarpa, Tomostima nemorosa
Name authority Greene: Pl. Baker. 3: 5. (1901) Linnaeus: Sp. Pl. 2: 643. (1753)
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