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 petrophila

Draba cinerea

Santa Rita Mountain Draba, Santa Rita Mountain whitlowgrass, Santa Rita whitlow grass

gray-leaf Draba, gray-leaf whitlow-grass
Habit Perennials; (cespitose, long-lived); caudex simple or branched (covered with persistent petioles), not scapose. Perennials; (cespitose); caudex simple or branched; rarely scapose.
Stems

usually unbranched, rarely branched, 0.3–1.9(–2.8) dm, moderately to densely hirsute throughout, trichomes simple, 0.2–1.3 mm, with short-stalked to subsessile, cruciform, 0.02–0.4 mm, and 2-rayed ones, 0.3–0.9 mm.

unbranched, (0.3–)0.5–1.6(–2.7) dm, pubescent throughout, trichomes 4–10-rayed, 0.1–0.3 mm, (often some rays branched, simple trichomes sparse, to 0.6 mm).
Basal leaves

rosulate; petiolate;

petiole ciliate, (trichomes simple, 0.4–1.5 mm);

blade oblanceolate, 1–5(–6) cm × 2–5(–10) mm, margins usually entire, rarely denticulate, surfaces pubescent, abaxially with stalked, cruciform trichomes, 0.07–0.5 mm, adaxially often similar, sometimes with fewer, simple and 2-rayed trichomes, 0.4–1.3 mm.

rosulate; petiolate;

petiole base and proximalmost margin ciliate, (trichomes simple, 0.2–0.8 mm);

blade oblanceolate to narrowly obovate or linear-lanceolate, 0.4–1.5 cm × 1–5 mm, margins usually entire, rarely with 1 tooth on each side, surfaces densely pubescent with minutely stalked, stellate, 8–12-rayed, trichomes 0.1–0.25 mm, (midvein obscure abaxially, apex trichomes simple).
Cauline leaves

3–10;

sessile;

blade ovate to lanceolate or oblong, margins entire or denticulate, surfaces pubescent as basal.

0–3(–5);

sessile;

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

10–37(–58)-flowered, ebracteate, elongated in fruit;

rachis not flexuous, pubescent as stem.

(3–)5–17(–24)-flowered, ebracteate, elongated in fruit;

rachis not flexuous, pubescent as stem.
Flowers

sepals oblong, 2–3.5 mm, pubescent, (trichomes simple and 2-rayed);

petals yellow, oblanceolate, 3.5–6 × 1.2–1.8 mm;

anthers oblong, 0.8–1 mm.

sepals ovate, 1.7–2.5 mm, pubescent, (trichomes simple and short-stalked, 2- or 3-rayed);

petals white, spatulate to obovate, 3.5–4.5 × 1.5–2 mm;

anthers ovate, 0.3–0.4 mm.
Fruiting pedicels

divaricate-ascending, straight, 4–10 mm, pubescent throughout, trichomes simple (0.1–0.5 mm) and subsessile, 2–4-rayed, (0.03–0.2 mm).

divaricate-ascending or ascending, straight, (3–)4–7(–9) mm, pubescent as stem.
Fruits

lanceolate to elliptic, often strongly twisted, flattened, 5–11 × 2–3 mm;

valves puberulent at least along margin, trichomes simple, antrorse, 0.03–0.15 mm;

ovules 14–24 per ovary;

style 0.8–1.8(–2.5) mm.

oblong to elliptic, plane, slightly flattened, 5–8 × 2–3 mm;

valves pubescent, trichomes short-stalked, 2–5-rayed, 0.05–0.3 mm, (some rays branched);

ovules 20–36(–42) per ovary;

style (0.1–)0.2–1 mm.
Seeds

ovoid, 1–1.4 × 0.6–0.9 mm.

ovoid, 0.6–0.8 × 0.4–0.6 mm.
2n

= 48.

Draba petrophila

Draba cinerea
Phenology Flowering Jul–Sep. Flowering Jun–Jul.
Habitat Crevices, ledges of cliffs Rock outcrops, ridges, meadows, gravel beaches, stream banks, alluvial fans
Elevation 1200-2800 m (3900-9200 ft) 0-500 m (0-1600 ft)
Distribution
from FNA
AZ
[WildflowerSearch map]
[BONAP county map]
from FNA
AK; BC; NT; NU; ON; QC; SK; YT; Greenland; Europe (Finland, Norway, n Russia); e Asia (Russian Far East, Siberia)
[BONAP county map]
Discussion

Draba petrophila is often broadly circumscribed to include the taxon herein called D. viridis. For a discussion of the differences between these species and the closely related D. helleriana, see I. A. Al-Shehbaz and M. D. Windham (2007). Draba petrophila, in the strict sense, is known only from Cochise, Pima, and Santa Cruz counties in southeastern Arizona.

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

Draba cinerea is a polymorphic species in which tetraploid, hexaploid, heptaploid, and octoploid chromosome counts (all based on x = 8) have been reported (e.g., R. C. Rollins 1993). Although we have not seen the type collection, we tentatively consider the taxon to be hexaploid, which is the predominant ploidy level throughout the species range, including North America, and also from its type region in Siberia.

Hexaploid Draba cinerea is closely related to decaploid (2n = 80) D. arctica, from which it is distinguished with difficulty. In general, D. cinerea has 1–3(–5)-leaved stems, basal leaf blades usually not terminated with simple trichomes and with obscure midveins abaxially, petals 3.5–4.5 mm, and seeds 0.6–0.8 × 0.4–0.6 mm. By contrast, D. arctica has leafless or 1(–3)-leaved stems, basal leaf blades terminated with simple or 2-rayed trichomes and with midveins distinct abaxially, petals 3.5–6 mm, and seeds (0.8–)0.9–1.1 × (0.6–)0.7–0.8 mm.

(Discussion copyrighted by Flora of North America; reprinted with permission.)
Source FNA vol. 7, p. 329. FNA vol. 7, p. 300.
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. 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. 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. 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. helleriana var. blumeri, D. helleriana var. petrophila D. magellanica subsp. cinerea
Name authority Greene: Pittonia 4: 17. (1899) Adams: Mém Soc. Imp. Naturalistes Moscou 5: 103. (1817)
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

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