Flora of North America species comparison

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Draba asprella var. stelligera

Draba asprella

rough Draba

rough Draba, rough whitlowgrass

Habit

Perennials; (cespitose); caudex branched (with some persistent leaf bases); scapose.

Stems

unbranched, (0.4–)0.6–1.5(–2.7) dm, pubescent throughout, trichomes simple, 0.5–1.5 mm, and 2–4-rayed ones, 0.05–0.3 mm, (sometimes 2–4-rayed ones distally).

Basal leaves

rosulate;

subsessile or shortly petiolate;

petiole ciliate throughout;

blade oblanceolate to spatulate or obovate, (0.6–)0.8–4.5(–6) cm × 2–12(–16) mm, margins usually entire, rarely obscurely dentate, (not ciliate), surfaces abaxially pubescent with stalked, (2–)4-rayed trichomes, 0.2–1 mm, adaxially with stalked, 2–4-rayed trichomes, 0.3–0.8 mm, and simple ones, 0.5–1.9 mm.

Cauline leaves

Racemes

(15–)30–75-flowered, ebracteate, elongated in fruit;

rachis not flexuous, pubescent, trichomes 2–4-rayed, sometimes with simple ones.

Flowers

sepals broadly ovate, 1.8–3.5 mm, pubescent, (trichomes simple and short-stalked, 2–4-rayed);

petals pale yellow, oblanceolate, 4–7 × 1.5–2.5 mm;

anthers ovate to oblong, 0.4–0.7 mm.

Fruiting pedicels

horizontal to divaricate-ascending, straight, 3–11(–16) mm, pubescent, trichomes 2–4-rayed, sometimes with simple ones.

Fruit(s)

valves puberulent, trichomes 2–4-rayed, 0.1–0.2 mm.

ovoid-ellipsoid to oblong, plane, inflated basally, 3–8 × 1.8–3.5 mm;

valves hirsute, trichomes simple and spurred, (0.2–)0.3–1 mm, or puberulent, trichomes short-stalked, 2–4-rayed, 0.1–0.2 mm;

ovules 8–12(–18) per ovary;

style 0.6–2(–2.5) mm.

Seeds

oblong, 0.9–1.2 × 0.6–0.8 mm.

= 30.

Draba asprella var. stelligera

Draba asprella

Phenology

Flowering Apr–Jul.

Habitat

On and around limestone and sandstone rock outcrops in pine-oak and pinyon-juniper communities

Elevation

1500-2400 m (4900-7900 ft)

Distribution

[BONAP county map]

[WildflowerSearch map]

[BONAP county map]

Discussion

Of conservation concern.

Variety stelligera is known from Coconino, Gila, and Yavapai counties in northern and central Arizona. The difference between vars. kaibabensis and stelligera rests on trichome density and the proportion of simple versus branched hairs on the leaves. These features are highly variable and we find no dependable characteristics separating populations on the North Rim of the Grand Canyon from those to the south.

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

Varieties 2 (2 in the flora).

Both R. C. Rollins (1993) and N. H. Holmgren (2005b) indicated that the chromosome number of Draba asprella is 2n = 32, but repeated counts by one of us (M. D. Windham 2000, unpubl.) show that the species consistently has 2n = 30. Rollins divided D. asprella into four varieties encompassing tremendous variation in trichome morphology. One of these (var. zionensis) is more closely related to D. sobolifera (Windham and L. Allphin, unpubl.) and is treated herein at species rank. Within D. asprella, in the strict sense, we recognize two varieties separated primarily by the type of trichomes found on the fruits. The distinctions are not absolute and there appear to be forms connecting the two, especially in Coconino County.

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

Key

1. Fruits hirsute, trichomes simple and unequally 2-rayed, (0.2-)0.3-1 mm.	var. asprella
1. Fruits puberulent, trichomes 2-4-rayed, 0.1-0.2 mm.	var. stelligera

Source

FNA vol. 7, p. 293.

Parent taxa

Brassicaceae > tribe Arabideae > Draba > Draba asprella

Brassicaceae > tribe Arabideae > Draba

Sibling taxa

D. asprella var. asprella

D. abajoensis, D. albertina, D. aleutica, D. alpina, D. aprica, D. arabisans, D. arctica, D. arctogena, D. argyrea, D. arida, 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. 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

Subordinate taxa

D. asprella var. asprella, D. asprella var. stelligera

Synonyms

D. asprella var. kaibabensis

Name authority

O. E. Schulz: in H. G. A. Engler, Pflanzenr. 89[IV,105]: 106. (1927)

Greene: Bull. Torrey Bot. Club 10: 125. (1883)

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).

Choose a data source: Flora of North America

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