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limestone Draba

Yukon whitlowgrass

Habit Perennials; (cespitose); caudex branched (with persistent leaves, branches sometimes terminating in sterile rosettes); scapose. Perennials; (short-lived); caudex simple or branched (with persistent leaf remains); not scapose.
Stems

unbranched, 0.2–0.9 dm, glabrous throughout.

branched, 0.4–2 dm, pubescent throughout, trichomes simple, 0.3–1.2 mm, and 2–6-rayed, 0.05–0.6 mm.

Basal leaves

rosulate;

sessile;

blade oblong to narrowly oblanceolate, 0.2–1 cm × 0.6–2(–4) mm, margins entire, (ciliate, trichomes simple, 0.1–0.5 mm, apex obtuse), surfaces glabrous.

rosulate;

subsessile;

blade oblanceolate to narrowly so, 0.3–1 cm × 0.5–2 mm, margins entire, (ciliate, trichomes simple, to 1.3 mm), surfaces pubescent, abaxially with (rigid), simple and 2-rayed trichomes, 0.4–1.2 mm, sometimes with short-stalked, 3–6-rayed ones, 0.1–0.3 mm, adaxially with simple trichomes.

Cauline leaves

0.

1–3;

sessile;

blade ovate to oblong, margins entire, surfaces pubescent as basal.

Racemes

3–8-flowered, ebracteate, considerably elongated in fruit;

rachis slightly flexuous, glabrous.

5–20-flowered, ebracteate, considerably elongated in fruit;

rachis not flexuous, pubescent as stem.

Flowers

sepals oblong, 1.7–2.5 mm, glabrous;

petals white, oblanceolate to obovate, 3.5–4.5 × 1.2–2 mm;

anthers ovate, 0.3–0.4 mm.

sepals ovate, 1.2–1.6 mm, pubescent, (trichomes simple and 2–4-rayed);

petals white, spatulate, 1.5–2 × 0.7–0.8 mm;

anthers ovate, ca. 0.2 mm.

Fruiting pedicels

divaricate-ascending to ascending, straight, 4–13 mm, glabrous.

erect to ascending, straight, 0.5–3 mm, pubescent as stem.

Fruits

oblong to narrowly so, slightly twisted, flattened, 5–9 × 1.5–3 mm;

valves glabrous;

ovules 8–16 per ovary;

style 0.3–0.9(–1.2) mm.

ovoid to oblong, plane, not flattened, 2–5 × 1.5–2 mm;

valves pubescent, trichomes short-stalked, 4- or 5-rayed, 0.05–0.3 mm;

ovules 36–52 per ovary;

style 0.1–0.3 mm.

Seeds

oblong, 0.9–1.3 × 0.6–0.8 mm.

oblong, 0.6–0.8 × 0.3–0.4 mm.

2n

= 32.

Draba oreibata

Draba yukonensis

Phenology Flowering May–Jul. Flowering late May–Jun.
Habitat Limestone cliffs, talus Open stony ridges on ancient beach in grassy areas and aspen stands
Elevation 1800-2700 m (5900-8900 ft) ca. 600 m (ca. 2000 ft)
Distribution
from FNA
ID
[BONAP county map]
from FNA
YT
[BONAP county map]
Discussion

R. C. Rollins (1993) and N. H. Holmgren (2005b) divided Draba oreibata into two varieties: the Idaho endemic var. oreibata and the Nevada endemic var. serpentina. As indicated by I. A. Al-Shehbaz and M. D. Windham (2007), the two taxa are morphologically distinct, have different chromosome numbers, and are separated by over 480 kilometers. They are treated herein as separate species, and distinguished by characteristics discussed by Al-Shehbaz and Windham. Draba oreibata, in the strict sense, is known from Blaine, Butte, Clark, Custer, and Lemhi counties.

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

Of conservation concern.

Draba yukonensis is known only from Kluane National Park, southwestern Yukon Territory.

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

Source FNA vol. 7, p. 325. FNA vol. 7, p. 346.
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. 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. 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. 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. zionensis
Name authority J. F. Macbride & Payson: Amer. J. Bot. 4: 257. (1917) A. E. Porsild: Publ. Bot. (Ottawa) 4: 37, plate 7. (1975)
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