Flora of North America species comparison

The green links below add additional plants to the comparison table. Blue links lead to other Web sites.
enable glossary links

Draba aurea

Draba micropetala

golden Draba, golden Draba whitlow-grass, golden whitlow-grass, twisted-pod Draba
Habit Perennials; (not cespitose); caudex simple or branched; not scapose. Perennials; caudex branched (with persistent leaf 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, (0.05–)0.15–0.7(–1.1) dm, pubescent throughout, sometimes sparsely so distally, trichomes stalked, 2–4-rayed, and simple, 0.05–0.6 mm.
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.

(not imbricate); rosulate; petiolate;

petiole (base thickened), margin ciliate, (trichomes coarse, simple and 2-rayed, 0.3–1.3 mm);

blade broadly oblanceolate to broadly obovate, 0.6–2 cm × 4–12 mm, margins entire, (apex obtuse to rounded, trichomes multibranched, subcruciform), surfaces pubescent abaxially with stalked, 2–4-rayed and, rarely, simple trichomes, 0.1–0.6 mm, adaxially glabrous or with mostly simple trichomes.
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.

2–7(–10)-flowered, ebracteate, often elongated in fruit;

rachis often 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 oblong, 1.8–2.5 mm, pubescent, (trichomes simple, with short-stalked, 2-rayed ones);

petals pale yellow, narrowly spatulate or oblanceolate, 2–3 × (0.7–)1–1.5 mm;

anthers ovate, 0.3–0.4 mm.
Fruiting pedicels

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

divaricate to ascending, straight, 1–3(–4) mm, pubescent as stem.
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.

elliptic-ovate, plane, slightly flattened, 5–10 × 2–3.2 mm;

valves often densely pubescent, trichomes simple and spurred, 0.1–0.5 mm;

ovules (16–)18–28 per ovary;

style 0.05–0.3 mm (stigma about as wide as style).
Seeds

oblong, 0.9–1.3 × 0.5–0.7 mm.

oblong, 1–1.1 × 0.5–0.6 mm.
2n

= 74.

= 48.

Draba aurea

Draba micropetala
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 Meadows, mesic tundra, swales, gravelly soils
Elevation (0-)700-4200 m ((0-)2300-13800 ft) 0-900 m (0-3000 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]
from FNA
AK; NT; NU; Greenland; Europe (Norway [Spitsbergen]); e Asia (Russian Far East, Siberia)
[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 micropetala, which was not listed by C. L. Hitchcock (1941) or R. C. Rollins (1993), is frequently confused with the closely related tetraploid (2n = 32) D. pauciflora. It is distinguished from the latter by having elongated (versus congested) fruiting racemes, narrower [2–3.2 versus (3–)3.5–5 mm] and elliptic-ovate (versus obovate) fruits, more [(16–)18–28 versus 8–16(–20)] seeds per fruit, and obtuse to rounded (versus subacute to acute) leaf apices with multibranched, subcruciform (versus simple and/or 2-branched) trichomes.

(Discussion copyrighted by Flora of North America; reprinted with permission.)
Source FNA vol. 7, p. 294. FNA vol. 7, p. 319.
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. 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. 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. micropetala, D. oblongata subsp. minuta, D. pauciflora var. micropetala
Name authority Vahl ex Hornemann: Fors. Oecon. Plantel. ed. 2, 599. (1806) Hooker: in W. E. Parry, App. Parry J. Sec. Voy., 385. (1825)
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).



Type/paste one or more Latin names into the boxes above; matching taxa will show up below the box as you type. You can use the up/down arrow keys to move through the list.

(If the plant you're looking for doesn't show up in the auto-complete list, that means it either isn't described in Flora of North America yet, or it's listed under a synonym. And please note that Flora of North America is still missing several plant families, including Fabaceae, Apiaceae, Boraginaceae, and Polemoniaceae.)

Choose a data source: Flora of North America, UW Burke Herbarium

The species comparison tool is brought to you by:
Northwest Wildflowers