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arctic Draba, Austrian Draba, Austrian whitlow-grass

Siberian whitlowgrass

Habit Perennials; (sometimes cespitose); caudex simple or branched (with persistent leaf bases); usually scapose. Perennials; (stoloniferous); caudex branched (sparsely covered with persistent petiole remains, branches slender, creeping); scapose.
Stems

unbranched, (0.2–)0.3–1(–1.3) dm, glabrous.

(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;

petiole (obscure), margin ciliate, (trichomes simple or 2-rayed, 0.25–0.6 mm);

blade linear to oblanceolate or narrowly obovate, (0.3–)0.4–1.2(–1.6) cm × 1–3(–4) mm, margins usually entire, rarely toothed, surfaces abaxially pubescent or glabrous, trichomes simple, sometimes with fewer, short-stalked, 2-rayed ones, (midvein prominent), adaxially often glabrous.

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

0–2;

sessile;

blade oblong to ovate, margins entire, (ciliate).

0.

Racemes

(2 or) 3–11(–14)-flowered, usually ebracteate, rarely proximalmost flowers bracteate, elongated in fruit;

rachis not flexuous, glabrous.

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

rachis not flexuous (straight), glabrous.

Flowers

sepals (green or purplish), ovate, 1.2–2.2 mm, glabrous or pubescent, (trichomes simple);

petals white, spatulate, 2–2.5 × 0.8–1.5 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

divaricate-ascending, often straight, (1–)2–5(–6) mm, glabrous.

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

Fruits

elliptic-lanceolate to oblong, plane, flattened, 3–8(–9) × 1.5–2 mm;

valves glabrous;

ovules 12–24 per ovary;

style 0.05–0.2(–0.3) 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

oblong to elliptic, 0.8–1 × 0.5–0.6 mm.

(brown), ovoid, 0.9–1.2 × 0.5–0.6 mm.

2n

= 16.

= 16.

Draba fladnizensis

Draba sibirica

Phenology Flowering Jun–Aug. Flowering May–Jul.
Habitat Rock outcrops and talus, alpine meadows, sandy gravel Wet places on rocky slopes
Elevation 0-1400 m at higher latitudes, 3000-3800 m at lower latitudes (0-4600 ft at higher latitudes, 9800-12500 ft at lower latitudes) 0-300 m (0-1000 ft)
Distribution
from FNA
AK; CO; UT; WY; BC; NT; NU; QC; YT; Greenland; c Europe; s Europe; Asia; circumpolar and high alpine areas
[WildflowerSearch map]
[BONAP county map]
from USDA
Greenland; Europe (Russia); Asia (Caucasus, Iran, Russian Far East, Siberia, Turkey, central republics)
[BONAP county map]
Discussion

Rollins reduced Draba pattersonii to a variety of D. fladnizensis and separated the two primarily on plant size and minor differences in fruit shape. Examination of D. fladnizensis specimens collected throughout Europe and North America reveals that the alleged differences between the two taxa are artificial. The type material of D. pattersonii, which was collected in Colorado, is a mixture of plants highly variable in their type of indumentum. The specimens have no flowers, but the habit, fruits, and leaves are nearly indistinguishable from those of D. fladnizensis from higher latitudes.

In the absence of flowers, the white-flowered Draba fladnizensis (2n = 16) is often confused with the yellow-flowered D. crassifolia (2n = 40). The latter is an annual or short-lived perennial that rarely forms a well-developed caudex, whereas D. fladnizensis almost always produces a distinct caudex. Although most individuals of both species are scapose, they occasionally produce one or two cauline leaves. The cauline leaves are usually glabrous in D. crassifolia and ciliate in D. fladnizensis; in the latter, the distalmost cauline leaf usually subtends the proximalmost flower. Finally, the seeds in D. fladnizensis are slightly larger (0.8–0.1 × 0.5–0.6 versus 0.7–0.8 × 0.4–0.5 mm) than those of D. crassifolia, though the reliability of this distinction needs to be examined in greater detail. N. H. Holmgren (2005b) reported D. fladnizensis from central Nevada, but we have not seen any material of the species from that state.

(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. 307. 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. 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. 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. fladnizensis var. pattersonii, D. pattersonii, D. pattersonii var. hirticaulis, D. wahlenbergii Lepidium sibiricum, D. gmelinii, D. repens, D. sibirica subsp. arctica
Name authority Wulfen: in N. J. Jacquin, Misc. Austriac. 1: 147, plate 17, fig. 1. (1778) (Pallas) Thellung: Neue Denkschr. Schweiz. Naturf. Ges. 41: 318. (1907)
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