Flora of North America species comparison

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Draba aurea

Draba oxycarpa

golden Draba, golden Draba whitlow-grass, golden whitlow-grass, twisted-pod Draba
Habit Perennials; (not cespitose); caudex simple or branched; not scapose. Perennials; (cespitose); caudex branched (covered with persistent petiole remains); scapose.
Stems

sometimes branched distally, (0.5–) 1–3.5(–5.2) dm, pubescent throughout, trichomes simple (non-crisped), 0.4–1.3 mm, and 3–6-rayed ones, 0.1–0.5 mm.

unbranched, 0.2–1.1 dm, pubescent proximally, trichomes short-stalked, 2–5-rayed, 0.1–0.5 mm, (some rays spurred).
Basal leaves

rosulate; petiolate;

petiole (distinct or obscure) ciliate, (trichomes simple, to 0.8 mm);

blade oblanceolate to obovate, (0.4–)1–3.7(–5) cm × (1–)2–7(–10) mm, margins entire or denticulate, surfaces pubescent, trichomes stalked, (2–)4–7 (or 8)-rayed, 0.2–0.5(–0.6) mm.

rosulate; petiolate;

petiole base and margin ciliate, (trichomes simple, 0.3–1 mm);

blade oblanceolate to lanceolate, 0.8–2.2 cm × 2–6 mm, margins often entire, surfaces pubescent abaxially with stalked, 2–5-rayed, stellate trichomes, 0.1–0.4 mm, often some rays spurred and trichomes appearing subdendritic, rarely glabrate, or with simple and 2-rayed ones, (midvein obscure abaxially, not thickened), adaxially glabrous or sparsely pubescent with simple trichomes, sometimes with long-stalked, 2- or 3-rayed ones.
Cauline leaves

5–20(–26);

sessile;

blade oblong to lanceolate or ovate, margins entire or dentate, surfaces pubescent as basal, sometimes adaxially with simple trichomes.

0.
Racemes

(10–)18–52(–72)-flowered, usually bracteate on proximalmost 1–12(–17) flowers, rarely ebracteate, elongated in fruit;

rachis not flexuous, pubescent as stem.

(2–)4–13-flowered, ebracteate, (subcorymbose), not elongated in fruit;

rachis not flexuous, pubescent as stem.
Flowers

sepals (green or yellowish), oblong, 2.2–3 mm, pubescent, (trichomes simple and branched);

petals yellow, oblanceolate, 3.5–5 × 1.5–2.5 mm;

anthers ovate, 0.4–0.5 mm.

sepals (grayish white), ovate to broadly so, 2.5–3 mm, pubescent, (trichomes simple and stalked, 2-rayed);

petals creamy white to yellow, broadly obovate, 3.5–5 × 2.5–3.5 mm;

anthers ovate, 0.4–0.5 mm.
Fruiting pedicels

divaricate-ascending to ascending or suberect, straight, 3–13(–20) mm, pubescent as stem.

subhorizontal to divaricate-ascending (not appressed to rachis), often slightly curved upward, 4–7(–10) mm, pubescent, trichomes simple (0.4–1 mm), and 2–4-rayed (0.1–0.4 mm).
Fruits

(often subappressed to rachis), lanceolate to linear-lanceolate or narrowly oblong, slightly twisted or plane, flattened, (6–)9–14(–17) × 2–3.5 mm;

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

ovules 28–38(–44) per ovary;

style 0.5–1.2(–1.5) mm.

ovate to ovate-oblong, plane, flattened, 5–10 × 3–5 mm;

valves puberulent along replum, trichomes simple, 0.1–0.3 mm;

ovules (16–)18–28 per ovary;

style 0.2–0.6 mm (stigma as wide as style).
Seeds

oblong, 0.9–1.3 × 0.5–0.7 mm.

(black), ovoid, 1–1.3 × 0.6–0.8 mm.
2n

= 74.

= 64.

Draba aurea

Draba oxycarpa
Phenology Flowering Jun–Aug. Flowering Jun–Jul.
Habitat Rock outcrops, talus, damp gullies and meadows, subalpine conifer woodlands, alpine slopes and turf, tundra, road banks, river gravel Rocky soils
Elevation (0-)700-4200 m ((0-)2300-13800 ft)
Distribution
from FNA
AK; AZ; CO; ID; MT; NM; NV; SD; UT; WA; WY; AB; BC; MB; NF; NT; NU; ON; QC; SK; YT; Greenland
[WildflowerSearch map]
[BONAP county map]
Greenland; Europe (Norway [including Spitsbergen], Sweden); Atlantic Islands (Iceland)
[BONAP county map]
Discussion

Draba aurea is extremely variable in plant size, number of cauline leaves, number of bracteate flowers, style length, and fruit size, shape, orientation, twisting, and indumentum. Much of the variation in the number of bracts, style length, fruit twisting, and growth habit occurs in Greenland, where the type specimen was collected and where the species is found near sea level.

The highly deviant chromosome counts (e.g., 2n = 40 + 1, 64, 82) listed by R. C. Rollins (1993) and S. I. Warwick and I. A. Al-Shehbaz (2006) are mostly unvouchered and have to be disregarded; counts of 2n = ca. 80 have been re-assigned to Draba glabella. Published (G. A. Mulligan 2002) and unpublished counts made by Mulligan and M. D. Windham from Alaska, British Columbia, Colorado, Quebec, Utah, and Yukon indicate that the most common chromosome number of D. aurea is 2n = 74 (or 72). This suggests that the species is an allopolyploid (hexaploid or higher), incorporating genomes from both euploid and aneuploid lineages (M. A. Beilstein and Windham 2003). Detailed cytological and molecular studies are much needed to fully understand this widely distributed and highly variable species.

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

Draba oxycarpa is an octoploid that most closely resembles the decaploid D. alpina. It is distinguished from that species by having creamy white to pale yellow (versus bright yellow) petals, gray-green (versus purplish tinged) sepals, petals 2.5–3.5 (versus 1.7–2.5) mm wide, stems pubescent proximally with primarily branched (versus primarily simple) trichomes, nearly black (versus pale brown) seeds, and ovate to ovate-oblong (versus elliptic) fruits 3–5 (versus 2–3) mm wide.

(Discussion copyrighted by Flora of North America; reprinted with permission.)
Source FNA vol. 7, p. 294. FNA vol. 7, p. 325.
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. 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
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. 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. aurea var. aureiformis, D. aurea var. leiocarpa, D. aurea var. luteola, D. aureiformis, D. aureiformis var. leiocarpa, D. bakeri, D. decumbens, D. henneana var. maccallae, D. luteola, D. luteola var. minganensis, D. maccallae, D. minganensis, D. surculifera, D. uber D. alpina var. oxycarpa, D. gredinii
Name authority Vahl ex Hornemann: Fors. Oecon. Plantel. ed. 2, 599. (1806) Sommerfelt: Mag. Naturvidensk., n. s. 1: 240. (1833)
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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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