Flora of North America species comparison

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Draba fladnizensis

Draba stenoloba

arctic Draba, Austrian Draba, Austrian whitlow-grass

Alaska Draba, Alaska whitlow-grass
Habit Perennials; (sometimes cespitose); caudex simple or branched (with persistent leaf bases); usually scapose. Biennials or perennials; (short-lived, not cespitose); caudex simple (not fleshy); scapose.
Stems

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

often unbranched, (0.2–)0.4–3(–3.4) dm, pubescent proximally, usually glabrous distally, rarely sparsely pubescent, trichomes short-stalked, 2–4-rayed, 0.1–0.4(–0.5) mm.
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;

petiole (obscure), margin ciliate, (trichomes simple, 0.2–0.4 mm);

blade oblanceolate to obovate, 0.4–2.6(–3.1) cm × 1.5–7(–10) mm, margins entire or denticulate, (ciliate as petiole), surfaces pubescent, abaxially with short-stalked, 3- or 4-rayed trichomes, 0.1–0.5 mm, adaxially with simple and stalked, 2–4-rayed trichomes, 0.1–0.5 mm.
Cauline leaves

0–2;

sessile;

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

(0 or) 1 or 2 (3 or 4);

sessile;

blade elliptic to lanceolate or ovate, margins toothed, surfaces pubescent, abaxially with short-stalked 3- or 4-rayed trichomes, adaxially with simple and short-stalked, 2–4-rayed trichomes.
Racemes

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

rachis not flexuous, glabrous.

(2–)4–10(–15)-flowered, ebracteate, elongated in fruit;

rachis not flexuous, usually glabrous, rarely sparsely pubescent.
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.

(chasmogamous, petaliferous);

sepals (green or purplish), oblong, 1.5–2.5 mm, glabrous or pubescent, (trichomes simple);

petals yellow, oblanceolate, 2.5–3.5 × 0.6–1 mm;

anthers ovate, 0.25–0.4 mm.
Fruiting pedicels

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

horizontal to divaricate-ascending, straight, 3–14(–19) mm (subequaling or shorter than fruit), usually glabrous, rarely pubescent, trichomes 2–4-rayed.
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.

linear or, rarely, linear-elliptic, plane, flattened, (8–)10–17(–20) × 1.5–2 mm;

valves usually glabrous, rarely sparsely puberulent, trichomes simple;

ovules 24–36 per ovary;

style 0.01–0.15 mm.
Seeds

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

ovoid, 0.9–1 × 0.5–0.6 mm.
2n

= 16.

= 40.

Draba fladnizensis

Draba stenoloba
Phenology Flowering Jun–Aug. Flowering Jun–Jul.
Habitat Rock outcrops and talus, alpine meadows, sandy gravel Grassy knolls, glacial moraines and creek banks, mesic meadows, alpine thickets
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) 600-2300 m (2000-7500 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 FNA
AK; OR; WA; AB; BC; YT
[WildflowerSearch map]
[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 stenoloba is occasionally confused with D. albertina, but is easily recognized by having exclusively 2–4-rayed (versus mostly simple) trichomes on stems proximally. It is rarely encountered and apparently confined to the Pacific Northwest. In contrast, D. albertina is common and widespread in the mountains of western North America.

(Discussion copyrighted by Flora of North America; reprinted with permission.)
Source FNA vol. 7, p. 307. FNA vol. 7, p. 340.
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. sibirica, D. sierrae, D. simmonsii, D. smithii, D. sobolifera, D. spectabilis, D. sphaerocarpa, D. sphaeroides, D. standleyi, 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 D. acinacis, D. hirta var. siliquosa, D. macouniana, D. nemorosa var. stenoloba, D. nitida var. praelonga, D. oligantha, D. stenoloba var. oligantha
Name authority Wulfen: in N. J. Jacquin, Misc. Austriac. 1: 147, plate 17, fig. 1. (1778) Ledebour: Fl. Ross. 1: 154. (1841)
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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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