Flora of North America species comparison

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Draba incerta

Draba pedicellata

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

Cusick's Draba, rocky-slope Draba, rocky-slope whitlow-grass, stalk whitlow-cress
Habit Perennials; (cespitose, often pulvinate); caudex branched (dense with persistent leaf remains, branches sometimes terminating in sterile rosettes); scapose. Perennials; (loosely cespitose); caudex branched (with persistent leaf bases, branches sometimes terminating in sterile rosettes); 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).

unbranched, (0.15–)0.3–1.3(–1.6) dm, pubescent proximally, glabrous or nearly so distally, trichomes 2- or 3-rayed and simple, 0.1–1 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;

blade oblanceolate to obovate, 0.4–1.6(–2) cm × 2–4(–6) mm, margins entire, (not ciliate), surfaces pubescent with stalked, 2–4-rayed trichomes, 0.2–0.9 mm, rarely adaxially with simple trichomes, (midvein obscure abaxially).
Cauline leaves

usually 0 (or 1, as a bract);

sessile;

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

0.
Racemes

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

rachis not flexuous, glabrous or pubescent as stem.

3–20(–27)-flowered, ebracteate, slightly to considerably elongated in fruit;

rachis straight or flexuous, usually glabrous, rarely 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, 1.8–2.5 mm, glabrous or pubescent, (trichomes simple and branched);

petals yellow, spatulate, 3.5–5.5 × 1.5–2.2 mm;

anthers ovate, 0.4–0.5 mm.
Fruiting pedicels

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

divaricate to horizontal, straight or curved upward (expanded basally or not), 4–9(–13) mm, glabrous or pubescent, trichomes simple and 2–4-rayed.
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.

lanceolate to ellipsoid or ovoid, plane (not curved), inflated or slightly flattened, (4.2–)5.3–10(–13) × 2.5–4.5(–5.5) mm;

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

ovules 8–16 per ovary;

style 0.3–1(–1.2) mm.
Seeds

oblong, 1.1–1.5 × 0.7–1 mm.

oblong, 1.2–1.6 × 0.7–0.9 mm.
2n

= 112.

= 20.

Draba incerta

Draba pedicellata
Phenology Flowering Jun–Aug. Flowering May–Jul.
Habitat Rock outcrops, talus, gravelly areas, tundra Rock outcrops, talus, steep gravel slopes in pinyon-juniper, mixed conifer, and subalpine meadow communities
Elevation 0-3300 m (0-10800 ft) 2300-3800 m (7500-12500 ft)
Distribution
from FNA
AK; CO; ID; MT; NV; UT; WA; WY; AB; BC; QC; YT
[WildflowerSearch map]
[BONAP county map]
from FNA
NV; UT
[WildflowerSearch map]
[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.)

Draba pedicellata is known from Elko, Eureka, Nye, and White Pine counties in northeastern Nevada and to Tooele County in northwestern Utah. It was considered a variety of D. cusickii by R. C. Rollins (1993); chromosome number, morphology, and geographic distribution suggest a closer relationship to D. sphaeroides. For a detailed discussion and comparison of these species, consult M. D. Windham (2004). N. H. Holmgren (2005b) divided D. pedicellata into two varieties: var. pedicellata, which is found on limestone throughout the species range, and var. wheelerensis, which is found on non-calcareous substrates in White Pine County. Although var. wheelerensis has slightly more spreading pedicels on somewhat more flexuous rachises, it appears to be little more than a dwarf alpine form of the species.

(Discussion copyrighted by Flora of North America; reprinted with permission.)
Source FNA vol. 7, p. 313. FNA vol. 7, p. 328.
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. 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. 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 D. cusickii var. pedicellata, D. pedicellata var. wheelerensis
Name authority Payson: Amer. J. Bot. 4: 261. (1917) (Rollins & R. A. Price) Windham: Madroño 50: 221. (2004)
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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