FNA: Draba breweri vs. Draba argyrea

	Draba breweri	Draba argyrea
	Brewer's whitlow grass, cushion Draba	silver Draba
Habit	Perennials; (cespitose, grayish pubescent); caudex branched (sometimes covered with persistent leaf bases, branches short, compact); sometimes scapose.	Perennials; caudex branched (branches loose, creeping, sometimes terminating in sterile shoots); scapose.
Stems	unbranched, (0.1–)0.2–1(–1.5) dm, pubescent throughout, trichomes stalked, 4–10-rayed, 0.1–0.3 mm.	unbranched, (0.2–)0.3–0.8(–1.1) dm, pubescent proximally, glabrous distally, trichomes short-stalked to subsessile, 5–8-rayed, 0.05–0.2 mm.
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; subsessile; petiole base and margin not ciliate, (midvein obscure abaxially); blade oblanceolate to obovate, 0.3–0.7(–1.2) cm × 1–2.5(–4) mm, margins entire, surfaces canescent with short-stalked, 8–12-rayed, stellate trichomes, 0.1–0.2 mm.
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).	2–8(–12)-flowered, ebracteate, elongated in fruit; rachis slightly flexuous, usually glabrous, rarely sparsely pubescent as stem.
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 ovate, 2–3 mm, pubescent, (trichomes 4–6-rayed); petals yellow, oblanceolate, 4–6 × 1.5–3 mm; anthers ovate, 0.5–0.6 mm.
Fruiting pedicels	ascending, (sometimes slightly appressed to rachis), straight, 1.5–3(–4) mm, pubescent as rachis.	divaricate-ascending, straight or slightly curved upward, (4–)5–12(–19) 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.	lanceolate to elliptic or ovate, plane or slightly twisted, flattened, 5–11 × 2–3.5(–4.5) mm, (symmetric); valves often puberulent, sometimes glabrous, trichomes simple and subsessile, 2–4-rayed, 0.03–0.2 mm; ovules 8–14 per ovary; style (0.7–)1–1.8(–2.4) mm.
Seeds	ovoid, 0.5–0.7 × 0.3–0.5 mm.	oblong, 1.2–1.8 × 0.8–1.1 mm.
2n	= 32.	= 36.

	Draba breweri	Draba argyrea
Phenology	Flowering Jul–Aug.	Flowering Apr–Jul.
Habitat	Rock outcrops, talus, exposed ridges, alpine areas	Rock crevices, ledges, talus slopes
Elevation	3100-4100 m (10200-13500 ft)	1000-3100 m (3300-10200 ft)
Distribution	CA [WildflowerSearch map] [BONAP county map]	ID [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.)	M. A. Beilstein and M. D. Windham (2003) hypothesized that Draba argyrea is an allopolyploid derived through hybridization between D. lonchocarpa and D. sphaerocarpa. The species is restricted to Blaine, Boise, Custer, and Elmore counties in central Idaho. (Discussion copyrighted by Flora of North America; reprinted with permission.)
Source	FNA vol. 7, p. 297.	FNA vol. 7, p. 292.
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. 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. 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	D. breweri var. sublaxa	D. argyrea var. glabrescens
Name authority	S. Watson: Proc. Amer. Acad. Arts 23: 260. (1888)	Rydberg: Bull. Torrey Bot. Club 30: 251. (1903)
Web links	Local floras: CA Local Web sites: CalFlora, CalPhotos WildflowerSearch iNaturalist (observations) USDA Plants Database LBJ Wildflower Center SEINet Plants of the World Online Encyclopedia of Life Wikipedia Google Image Search	Local Web sites: PNW Herbaria WildflowerSearch iNaturalist (observations) USDA Plants Database LBJ Wildflower Center SEINet Plants of the World Online Encyclopedia of Life Wikipedia Google Image Search

Draba argyrea

Brewer's whitlow grass, cushion Draba

silver Draba

Habit

Perennials; (cespitose, grayish pubescent); caudex branched (sometimes covered with persistent leaf bases, branches short, compact); sometimes scapose.

Perennials; caudex branched (branches loose, creeping, sometimes terminating in sterile shoots); scapose.

Stems

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

unbranched, (0.2–)0.3–0.8(–1.1) dm, pubescent proximally, glabrous distally, trichomes short-stalked to subsessile, 5–8-rayed, 0.05–0.2 mm.

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;

subsessile;

petiole base and margin not ciliate, (midvein obscure abaxially);

blade oblanceolate to obovate, 0.3–0.7(–1.2) cm × 1–2.5(–4) mm, margins entire, surfaces canescent with short-stalked, 8–12-rayed, stellate trichomes, 0.1–0.2 mm.

Cauline leaves

0–3(–6);

sessile;

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

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).

2–8(–12)-flowered, ebracteate, elongated in fruit;

rachis slightly flexuous, usually glabrous, rarely sparsely pubescent as stem.

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 ovate, 2–3 mm, pubescent, (trichomes 4–6-rayed);

petals yellow, oblanceolate, 4–6 × 1.5–3 mm;

anthers ovate, 0.5–0.6 mm.

Fruiting pedicels

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

divaricate-ascending, straight or slightly curved upward, (4–)5–12(–19) 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.

lanceolate to elliptic or ovate, plane or slightly twisted, flattened, 5–11 × 2–3.5(–4.5) mm, (symmetric);

valves often puberulent, sometimes glabrous, trichomes simple and subsessile, 2–4-rayed, 0.03–0.2 mm;

ovules 8–14 per ovary;

style (0.7–)1–1.8(–2.4) mm.

Seeds

ovoid, 0.5–0.7 × 0.3–0.5 mm.

oblong, 1.2–1.8 × 0.8–1.1 mm.

= 32.

= 36.

Draba breweri

Draba argyrea

Phenology

Flowering Jul–Aug.

Flowering Apr–Jul.

Habitat

Rock outcrops, talus, exposed ridges, alpine areas

Rock crevices, ledges, talus slopes

Elevation

3100-4100 m (10200-13500 ft)

1000-3100 m (3300-10200 ft)

Distribution

[WildflowerSearch map]

[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.)

M. A. Beilstein and M. D. Windham (2003) hypothesized that Draba argyrea is an allopolyploid derived through hybridization between D. lonchocarpa and D. sphaerocarpa. The species is restricted to Blaine, Boise, Custer, and Elmore counties in central Idaho.

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

Source

FNA vol. 7, p. 297.

FNA vol. 7, p. 292.

Parent taxa

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. 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. 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

D. breweri var. sublaxa

D. argyrea var. glabrescens

Name authority

S. Watson: Proc. Amer. Acad. Arts 23: 260. (1888)

Rydberg: Bull. Torrey Bot. Club 30: 251. (1903)

Web links

Unless otherwise noted, all data comes from the online version of the Flora of North America, who have made most of their content available via a Creative Commons license (CC BY 4.0).

Choose a data source: Flora of North America

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Draba breweri

Draba argyrea

Draba breweri

Draba argyrea