Flora of North America species comparison

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Draba grayana

Draba pilosa

Gray's Draba
Habit Perennials; (densely cespitose); caudex branched (covered with persistent, somewhat thickened, dry petioles); not scapose. Perennials; (not stoloniferous); caudex branched (covered with persistent, dry leaves and midveins); scapose.
Stems

unbranched, 0.08–0.6 dm, densely to moderately pubescent throughout, trichomes simple and stalked, 2- or 3-rayed, 0.2–1 mm.

unbranched, 0.4–1.7 dm, glabrous or pubescent, trichomes simple, 0.2–0.9 mm, and fewer, 2–4-rayed, 0.1–0.6 mm.
Basal leaves

rosulate;

petiolate;

petiole ciliate, (trichomes simple, 0.2–1 mm);

blade linear to linear-oblanceolate, (0.4–)0.6–1.5(–2) cm × 1–2 mm, margins entire, (pubescent as petiole), surfaces pubescent abaxially with simple and stalked, 2- or 3-rayed trichomes, 0.1–0.4 mm, adaxially glabrate or subapically sparsely pubescent with simple trichomes.

(imbricate); rosulate;

petiolate;

petiole (base thickened), ciliate throughout;

blade linear to linear-oblanceolate, 0.5–1.5(–2.2) cm × 1–2.5(–4) mm, margins entire (thickened, ciliate, trichomes simple and 2-rayed, to 1.1 mm), surfaces pubescent, abaxially with simple trichomes, 0.3–1 mm, and 2–4-rayed ones, 0.1–0.5 mm, adaxially similar, or with only simple trichomes, (midvein prominent, thickened).
Cauline leaves

1–4;

sessile;

blade linear to linear-oblanceolate, margins entire, surfaces pubescent as basal.

0.
Racemes

5–12(–16)-flowered, usually ebracteate, rarely proximalmost flowers bracteate, slightly elongated in fruit;

rachis not flexuous, pubescent as stem.

(2–)4–12-flowered, ebracteate, usually elongated in fruit;

rachis not flexuous, glabrous or pubescent as stem.
Flowers

sepals ovate, 1.5–2 mm, pubescent, (trichomes simple and short-stalked, 2- or 3-rayed);

petals bright yellow, spatulate, 3–4.5 × 1–2 mm, (flared, clawed);

anthers ovate, 0.3–0.5 mm.

sepals ovate, 2–3.5 mm, pubescent, (trichomes simple and short-stalked, 2-rayed);

petals pale to bright yellow, obovate, 3.5–6 × 2–3.5 mm;

anthers ovate, 0.4–0.5 mm.
Fruiting pedicels

divaricate-ascending, straight or slightly curved upward, 1.5–6 mm, pubescent as stem.

divaricate-ascending, usually straight, rarely curved upward, 6–13 mm, glabrous or pubescent as stem.
Fruits

lanceolate to oblong-lanceolate, slightly twisted or plane, flattened, 4–12 × 1.5–3 mm;

valves glabrous or pubescent, trichomes simple, 0.07–0.2 mm;

ovules 16–20 per ovary;

style 0.4–1.2 mm.

elliptic to lanceolate, 5–11 × 3–4 mm, plane, flattened;

valves glabrous or puberulent with simple and short-stalked, 2-rayed trichomes, 0.07–0.3 mm;

ovules 12–20 per ovary;

style 0.4–0.9 mm (stigma about as wide as style).
Seeds

ovoid, 1–1.4 × 0.7–1 mm.

ovoid, 1.2–1.4 × 0.8–1 mm.
2n

= 24 ± 3.

Draba grayana

Draba pilosa
Phenology Flowering Jul–Aug. Flowering Jul–Aug.
Habitat Alpine tundra, fellfields, gravelly wet meadows Dry gravelly slopes, sandy places, wet tundra
Elevation 3500-4000 m (11500-13100 ft) 0-1300 m (0-4300 ft)
Distribution
from FNA
CO
[BONAP county map]
from FNA
AK; NT; NU; YT; e Asia (ne Russian Far East, n Siberia)
[BONAP county map]
Discussion

Of conservation concern.

Draba grayana is an apomictic species clearly related to D. exunguiculata, with which it is occasionally sympatric (see discussion of 36. D. exunguiculata for distinguishing features). It is known from Chaffe, Clear Creek, Larimer, Park, and Summit counties.

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

O. E. Schulz (1927) reduced Draba pilosa to a variety of the decaploid D. alpina and cited North American collections. The former species was not listed by C. L. Hitchcock (1941) or R. C. Rollins (1993). From D. alpina, D. pilosa is easily distinguished by having strongly thickened and persistent (versus not thickened) midveins and margins, and usually narrower leaf blades [1–2.5(–5) versus 2.5–6(–9) mm wide].

As recognized herein, Draba pilosa is broadly circumscribed to include perhaps two or three closely related taxa. All are scapose plants with large, yellow flowers and prominent, persistent midveins and petioles. Some Alaskan forms (e.g., Parker 7596, ALA), which grow in moist heath habitats, have leaves 3–5 mm wide, whereas the majority have narrower leaf blades rarely reaching 2.5 mm in width. Most plants assigned to this species have leaves with exclusively simple trichomes and often glabrous scapes. Others (e.g., Chesemore & Davies 13, Murray 3371, Parker & Batten 8954, all at ALA) have leaf blade surfaces and scapes with 2–4-rayed trichomes and blade margins ciliate with simple trichomes. One collection (Walker s.n., ALA) has a mixture of plants of both trichome types but no intermediates were found. Detailed molecular and cytological studies are needed on this complex to determine if more than one taxon is represented.

(Discussion copyrighted by Flora of North America; reprinted with permission.)
Source FNA vol. 7, p. 310. FNA vol. 7, p. 330.
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. graminea, D. grandis, 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. 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. streptocarpa var. grayana, D. alpicola D. alpina var. pilosa, D. aspera
Name authority (Rydberg) C. L. Hitchcock: Revis. Drabas W. N. Amer., 29. (1941) Adams ex de Candolle: in A. P. de Candolle, Syst. Nat. 2: 336. (1821)
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).



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