Flora of North America species comparison

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Draba incerta

Draba arida

whitlow-wort, Yellowstone Draba, Yellowstone Draba whitlow-wort, Yellowstone whitlow-grass, Yellowstone whitlow-wort

desert Draba
Habit Perennials; (cespitose, often pulvinate); caudex branched (dense with persistent leaf remains, branches sometimes terminating in sterile rosettes); scapose. Perennials; (cespitose); caudex branched (with persistent leaf remains, branches relatively short); not scapose.
Stems

unbranched, (0.2–)0.4–1.4(–2.1) dm, often pubescent throughout, sometimes glabrous distally, trichomes often simple and 2–5-rayed, 0.1–0.5 mm, (sometimes with mostly subpectinate ones).

usually unbranched, (0.3–)0.4–1 dm, pubescent throughout, trichomes simple and 2-rayed, 0.4–1.4 mm, and shorter, 2–4-rayed ones, 0.05–0.3 mm.
Basal leaves

rosulate; petiolate;

petiole (0–1 cm), ciliate throughout;

blade narrowly oblanceolate to linear, (0.4–)0.6–1.7(–2.5) cm × (1–)1.5–3.5(–5) mm, margins entire, (ciliate, trichomes usually simple, rarely 2-rayed, 0.2–1.1 mm), surfaces usually pubescent with short-stalked, pectinate trichomes, 0.15–0.5 mm, sometimes also with 4–6-rayed ones, (midvein usually obscure abaxially), sometimes glabrous adaxially.

rosulate;

subsessile;

petiole not ciliate;

blade obovate to spatulate or oblanceolate, 0.6–1.9(–2.4) cm × 2–5(–8) mm, (base ciliate, trichomes simple and 2-rayed), margins entire, surfaces abaxially pubescent with stalked, (2–)4-rayed trichomes, 0.3–0.6 mm, adaxially with simple and stalked, 2-rayed trichomes, 0.3–0.6 mm, and smaller, 3- or 4-rayed ones.
Cauline leaves

usually 0 (or 1, as a bract);

sessile;

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

(1 or) 2–5;

sessile;

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

3–14(–30)-flowered, usually ebracteate, rarely proximalmost flowers bracteate, elongated in fruit;

rachis not flexuous, glabrous or pubescent as stem.

12–40-flowered, ebracteate, slightly elongated in fruit;

rachis not flexuous, pubescent, trichomes simple and 2–4-rayed.
Flowers

sepals broadly ovate, 2.5–3.5(–4) mm, pubescent, (trichomes simple and 2- or 3-rayed);

petals yellow (fading white), oblanceolate to obovate, 4–6 × 1.5–2.5 mm;

anthers ovate, 0.3–0.5 mm.

sepals broadly ovate, 2–2.7 mm, pubescent, (trichomes simple and short-stalked, 2–4-rayed);

petals yellow, spatulate to oblanceolate, 3.5–5 × 1.4–2 mm;

anthers oblong, 0.4–0.6 mm.
Fruiting pedicels

ascending, straight, (2.5–)4–11(–27) mm, glabrous or pubescent, trichomes 2–5-rayed or pectinate.

horizontal to divaricate-ascending, straight, (3–)4–8 mm, pubescent, trichomes simple and 2–4-rayed (0.1–0.5 mm).
Fruits

broadly ovate to lanceolate, plane, flattened, 5–9(–11) × 2–4 mm;

valves glabrous or puberulent, trichomes simple and 2-rayed, 0.05–0.3 mm;

ovules 8–16(–20) per ovary;

style 0.2–0.9 mm.

elliptic or ovate to lanceolate, plane, slightly inflated basally, 4–7 × 2.5–3.5 mm;

valves pubescent, trichomes simple and stalked, 2–4-rayed, 0.05–0.4 mm;

ovules 8–12 per ovary;

style 0.5–1.2(–1.4) mm.
Seeds

oblong, 1.1–1.5 × 0.7–1 mm.

ovoid, 1–1.4 × 0.6–0.8 mm.
2n

= 112.

= 24.

Draba incerta

Draba arida
Phenology Flowering Jun–Aug. Flowering May–Jul.
Habitat Rock outcrops, talus, gravelly areas, tundra Rock crevices and gravelly soil in conifer and subalpine shrub communities
Elevation 0-3300 m (0-10800 ft) 2100-3400 m (6900-11200 ft)
Distribution
from FNA
AK; CO; ID; MT; NV; UT; WA; WY; AB; BC; QC; YT
[WildflowerSearch map]
[BONAP county map]
from FNA
NV
[BONAP county map]
Discussion

Draba incerta was shown by G. A. Mulligan (1972) to be sexually reproducing and 14-ploid with x = 8. It is often confused with the apomict D. oligosperma (2n = 32, 64). Draba incerta is readily separated from D. oligosperma by having well-formed (versus abortive) anthers and pollen, stalked (versus sessile) leaf trichomes, and ciliate (versus non-ciliate) basal leaves with obscure (versus prominent) midveins. Although both species have leafless scapes, one often finds a bract adnate to, or subtending, the proximalmost pedicel in D. incerta.

Draba incerta is found near sea level in Alaska.

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

Of conservation concern.

Draba arida is a sexually reproducing, diploid member of the D. ventosa complex that may have been involved in the origin of the more widespread apomictic triploids (M. A. Beilstein and M. D. Windham 2003). The species is known from the Monitor, Toiyabe, and Toquima ranges in Lander and Nye counties.

(Discussion copyrighted by Flora of North America; reprinted with permission.)
Source FNA vol. 7, p. 313. 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. 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. 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. 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. exalata, D. incerta var. laevicapsula, D. incerta var. peasei, D. laevicapsula, D. peasei
Name authority Payson: Amer. J. Bot. 4: 261. (1917) C. L. Hitchcock: Revis. Drabas W. N. Amer., 52, plate 3, fig. 23. (1941)
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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