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twisted Draba

shortstyle Draba

Habit Biennials; not scapose. Annuals or perennials; (short-lived); caudex often simple (poorly developed); not scapose.
Stems

usually branched, rarely unbranched, (0.3–)0.6–3(–4) dm, densely pubescent proximally, trichomes simple, 0.4–1.3 mm, with fewer 2–4-rayed ones, to 0.3 mm, (distally with mostly branched trichomes, with fewer, simple ones).

unbranched or branched, 0.6–3(–3.7) dm, pubescent throughout, trichomes simple, 0.4–0.9 mm, and 2–4-rayed, 0.05–0.4 mm.

Basal leaves

rosulate;

petiolate;

petiole base and margin ciliate, (trichomes simple, 0.2–0.7 mm);

blade lanceolate or oblanceolate to spatulate, 0.5–2.9 cm × 1–5(–9) mm, margins dentate, surfaces pubescent, abaxially with stalked, cruciform, or 2- or 3-rayed trichomes, 0.1–0.4 mm, (rarely with a branched ray), adaxially with simple trichomes, 0.1–0.7 mm, and stalked, 2–4-rayed ones.

rosulate;

subsessile;

petiole base ciliate, (trichomes simple, 0.3–0.9 mm);

blade oblanceolate, 1–3.5 cm × 4–7(–12) mm, margins entire or denticulate, surfaces pubescent, abaxially with stalked, (2–)4-rayed trichomes, 0.1–0.5 mm, adaxially with simple trichomes, 0.2–0.6 mm, with smaller, 2–4-rayed ones.

Cauline leaves

(15–)22–54(–76), (densely imbricate at least basally);

sessile;

blade ovate to oblong or lanceolate (base often densely bearded abaxially, trichomes simple, to 1.3 mm), margins dentate, surfaces pubescent as basal.

(1 or) 2–6(–8);

sessile;

blade lanceolate or oblanceolate to ovate, margins entire or denticulate, surfaces pubescent as basal.

Racemes

(11–)17–36(–48)-flowered, bracteate basally, elongated or not in fruit;

rachis not flexuous, pubescent as stems distally.

(5–)10–35(–47)-flowered, ebracteate, elongated in fruit;

rachis not flexuous, pubescent as stem.

Flowers

sepals ovate, 2–2.5 mm, pubescent, (trichomes simple and short-stalked, 2–4-rayed);

petals white, spatulate, 3.5–4.5 × 1–2 mm;

anthers ovate, 0.3–0.4 mm.

sepals ovate, 2–2.7 mm, pubescent, (trichomes simple and short-stalked, 2-rayed);

petals pale yellow (fading white), oblanceolate, 2.5–3.7 × 0.9–1.2 mm;

anthers ovate, 0.2–0.3 mm.

Fruiting pedicels

erect to ascending, (subappressed to rachis), straight, (1.5–)2.5–6(–13) mm, pubescent, trichomes 2–4-rayed and simple.

divaricate-ascending, straight or only slightly curved upward, (1.5–)3–8(–10) mm, pubescent throughout, trichomes simple and stalked, 2–4-rayed.

Fruits

oblong to linear-lanceolate or elliptic, slightly twisted or plane, flattened, 5–10(–12) × 1.5–2.5(–3) mm;

valves glabrous or pubescent, trichomes simple and short-stalked, 2–4-rayed, 0.05–0.3 mm;

ovules (24–)30–40 per ovary;

style 0.01–0.25 mm.

narrowly elliptic to lanceolate, plane, flattened, (7–)10–16(–19) × 2–3.5 mm;

valves pubescent, trichomes simple, spurred, and short-stalked, 2-rayed, 0.05–0.2(–0.3) mm;

ovules 20–36(–42) per ovary;

style 0.2–0.6(–0.8) mm.

Seeds

oblong, 0.7–1.1 × 0.5–0.6 mm.

oblong, 0.9–1.3 × 0.6–0.7 mm.

2n

= 32.

= 44.

Draba incana

Draba brachystylis

Phenology Flowering Jul–Aug. Flowering Jun–Jul.
Habitat Rock outcrops, talus, gravelly shores Fir and aspen communities, moist areas on rocky slopes
Elevation 0-200 m (0-700 ft) 1700-3000 m (5600-9800 ft)
Distribution
from FNA
MI; MN; MB; NB; NL; ON; PE; QC; Greenland; n Europe; c Europe (Russia)
[BONAP county map]
from FNA
UT
[BONAP county map]
Discussion

Of conservation concern.

Based on morphological and chromosomal data (L. Allphin and M. D. Windham, unpubl.), Draba brachystylis is hypothesized to be an allopolyploid derived through hybridization between D. albertina and D. santaquinensis. It is known to us only from Cache, Duchesne, Juab, Salt Lake, and Utah counties. C. L. Hitchcock (1941) indicated that the species grows in the Charleston Mountains of Clark County, Nevada, but we have not seen unequivocal material of it from that area.

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

Source FNA vol. 7, p. 312. FNA vol. 7, p. 297.
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. grayana, D. heilii, D. helleriana, D. hitchcockii, D. howellii, 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. 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. confusa, D. contorta, D. incana subsp. confusa, D. incana var. confusa, D. incana var. contorta
Name authority Linnaeus: Sp. Pl. 2: 643. (1753) Rydberg: Bull. Torrey Bot. Club 29: 240. (1902)
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