Flora of North America species comparison

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Draba simmonsii

Draba densifolia

dense-leaf Draba, dense-leaf whitlow-grass, Nuttall's Draba, Nuttall's whitlow-grass
Habit Perennials; caudex branched (with persistent leaf bases and petioles); scapose. Perennials; (cespitose, pulvinate); caudex branched (dense with persistent leaf remains, branches sometimes terminating in sterile rosettes); scapose.
Stems

unbranched, (0.15–)0.3–1.1(–1.3) dm, often pubescent throughout, sometimes sparsely pubescent distally, trichomes stalked, 2–4-rayed, and fewer, simple ones, 0.1–0.3(–0.6) mm.

unbranched, (0.05–)0.2–1(–1.7) dm, usually glabrous, rarely pubescent, trichomes usually simple, 0.3–0.8 mm, and 2–4 (or 5)-rayed, 0.1–0.6 mm, (rarely predominantly simple ones).
Basal leaves

(not imbricate); rosulate;

petiolate;

petiole (base somewhat thickened), margin ciliate, (trichomes simple, 0.5–1 mm);

blade oblong to oblong-lanceolate, 0.5–1.6 cm × 2–5 mm, margins entire (apex subacute to obtuse), surfaces pubescent throughout or glabrous adaxially, with simple and stalked, 2–4(–6)-rayed, stellate to subdendritic trichomes.

rosulate;

sessile;

blade linear to oblong or oblanceolate-linear, 0.3–0.9(–1.4) cm × 0.5–1.5(–2) mm, margins entire, (ciliate, trichomes simple, 0.3–1.2 mm), surfaces glabrous or sparsely pubescent, abaxially with short-stalked, 2–4-rayed trichomes, 0.1–0.3 mm (midvein prominent), adaxially rarely with subapical, simple trichomes.
Cauline leaves

0.

0.
Racemes

(2–)4–10(–14)-flowered, ebracteate, slightly elongated in fruit;

rachis not flexuous (straight), pubescent as stem.

2–10(–22)-flowered, ebracteate, not or slightly elongated in fruit;

rachis not or slightly flexuous, glabrous or pubescent as stem.
Flowers

sepals (purplish green), oblong, (2.5–)2.8–3.5(–3.8) mm, pubescent, (trichomes simple and sometimes short-stalked, 2-rayed);

petals pale yellow, narrowly obovate, (sides non-parallel), (3.5–)3.8–5.5(–5.8) × (2.5–)2.8–4(–4.6) mm, (emarginate);

anthers ovate, ca. 0.5 mm.

sepals ovate, 2–3 mm, usually sparsely pubescent, rarely glabrous, (trichomes simple and short-stalked, 2–4-rayed);

petals pale yellow (sometimes fading white), oblanceolate to obovate, 2–5 × 1–1.7(–2) mm;

anthers ovate or oblong, 0.4–0.6 mm.
Fruiting pedicels

divaricate, straight, 2.5–10 mm, pubescent as stem.

divaricate-ascending to ascending (not decurrent basally), straight, (0.7–)1.5–10(–25) mm, usually glabrous, rarely sparsely pubescent, trichomes predominantly simple (0.2–0.7 mm), sometimes 2–4 (or 5)-rayed, (0.1–0.5 mm).
Fruits

lanceolate, plane, slightly flattened, 5.5–9(–11) × 2.3–3.8 mm;

valves pubescent, trichomes simple, sometimes with fewer, 2-rayed ones, 0.1–0.3 mm;

ovules 16–24(–28) per ovary;

style 0.1–0.3 mm (stigma as wide as style).

ovoid or ovate-lanceolate, plane (not curved), flattened, (2.5–)3–6(–8) × 2–3 mm;

valves pubescent or puberulent, trichomes simple and short-stalked, 2–5-rayed, 0.1–0.4 mm;

ovules 4–12 per ovary;

style 0.3–0.6(–1) mm.
Seeds

(dark brown), oblong-ovate, 1–1.3 × 0.7–0.8 mm.

oblong to ovoid, 1.2–2(–2.6) × 0.9–1.2(–1.4) mm.
2n

= 36.

Draba simmonsii

Draba densifolia
Phenology Flowering late Jun–Jul. Flowering Jun–Aug.
Habitat Dry open ground, open patches in meadows or heath vegetation, outwash plains Rock outcrops and talus, rocky knolls, alpine ridges
Elevation 0-100 m (0-300 ft) 800-3700 m (2600-12100 ft)
Distribution
from FNA
NT; NU
[BONAP county map]
from FNA
AK; CA; ID; NV; OR; UT; WA; WY; AB; BC
[WildflowerSearch map]
[BONAP county map]
Discussion

Draba densifolia is one of the most highly variable North American members of the genus, as evidenced by the extensive synonymy. The species is an apomict (G. A. Mulligan 1976) and it occupies tremendous geographic, edaphic, and altitudinal ranges. In forms corresponding to the type of D. sphaerula, the flowering stems are 2-flowered, and the stems, leaves, and fruiting pedicels are to 5, 1.5, and 0.6 mm, respectively. By contrast, forms comparable to the type of D. caeruleomontana var. piperi have stems, leaves, and fruiting pedicels to 17, 1.3, and 2.5 cm, respectively. Between these remarkable extremes fall all of the other populations of the species.

Draba densifolia is sometimes confused with D. paysonii, which it resembles, in being a cespitose, scapose, and densely pulvinate perennial having narrowly linear or oblong to linear-oblanceolate leaf blades with strongly ciliate margins. It is easily distinguished from the latter by having glabrous adaxial leaf blade surfaces, only sparsely pubescent abaxial surfaces, and often glabrous fruiting pedicels and rachises.

(Discussion copyrighted by Flora of North America; reprinted with permission.)
Source FNA vol. 7, p. 337. FNA vol. 7, p. 306.
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. 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. 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. 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. alpina var. gracilescens D. caeruleomontana, D. caeruleomontana var. piperi, D. glacialis var. pectinata, D. globosa var. sphaerula, D. mulfordiae, D. nelsonii, D. oligosperma var. pectinata, D. pectinata, D. sphaerula
Name authority Elven & Al-Shehbaz: Novon 18: 326. (2008) Nuttall: in J. Torrey and A. Gray, Fl. N. Amer. 1: 104. (1838)
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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