Flora of North America species comparison

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Draba alpina

Draba macounii

alpine Draba

Macoun's Draba, Macoun's whitlow-grass
Habit Perennials; (cespitose); caudex branched (covered with persistent leaves or leaf remains); scapose. Perennials; (cespitose); caudex simple or branched (with persistent leaf bases, branches sometimes terminating in sterile rosettes); scapose.
Stems

unbranched, (0.3–)0.5–1.7(–2.8) dm, pubescent throughout, trichomes simple and 2-rayed, 0.3–0.8 mm, with 3–5-rayed ones, 0.1–0.3 mm.

unbranched, (0.06–)0.1–0.4(–0.6) dm, usually pubescent, rarely glabrous, trichomes simple and stalked, 2–4-rayed, 0.15–0.9 mm.
Basal leaves

rosulate; petiolate;

petiole base (not thickened), ciliate, (trichomes simple, 0.3–1 mm);

blade oblanceolate to obovate or lanceolate to oblong, 0.8–3(–4.5) cm × 2.5–6(–9) mm, margins entire, surfaces abaxially pubescent with stalked, 2–4-rayed trichomes, 0.1–0.5 mm, with simple ones (midvein obscure, not thickened), adaxially glabrous or sparsely pubescent with simple and stalked, 2–4-rayed trichomes.

rosulate;

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

blade oblanceolate to obovate, (0.4–)0.6–1(–1.5) cm × (1–)2–4 mm, margins entire, surfaces usually pubescent abaxially, rarely glabrous, with short-stalked, 2–5-rayed trichomes, 0.1–0.5 mm, adaxially glabrous or pubescent with simple and short-stalked, 2-rayed trichomes.
Cauline leaves

0.

0.
Racemes

6–18-flowered, ebracteate, considerably elongated in fruit;

rachis not flexuous, pubescent as stem.

3–10(–13)-flowered, ebracteate, (subumbellate), slightly elongated in fruit;

rachis not flexuous, usually pubescent as stem, rarely glabrous.
Flowers

sepals (purplish tinged), narrowly ovate, 2.5–3 mm, pubescent, (trichomes simple and fewer, stalked, 2-rayed);

petals bright yellow, narrowly obovate, 3.5–5 × 1.7–2.5 mm;

anthers ovate, 0.3–0.4 mm.

sepals ovate, 1.5–2.5 mm, glabrous or pubescent, (trichomes simple and short-stalked, 2- or 3-rayed);

petals pale yellow, spatulate, 2.7–4 × 1–2 mm;

anthers ovate, 0.2–0.3 mm.
Fruiting pedicels

ascending to divaricate-ascending, straight or, sometimes, slightly curved upwards, 4–14(–30) mm, pubescent, trichomes simple and 2–4-rayed.

horizontal to divaricate (not expanded basally), curved upward, 1.5–4.5(–6) mm, abaxially pubescent as stem, adaxially usually glabrous, rarely throughout.
Fruits

elliptic, plane, flattened, 6–10 × 2–3 mm;

valves glabrous or glabrescent, trichomes simple, (not confined to replum);

ovules 12–24 per ovary;

style 0.2–0.3 mm (stigma about as wide as style).

subglobose to ovoid or ellipsoid, plane, inflated at least basally, 4–8 × 2–4.5 mm;

valves glabrous;

ovules 10–14(–16) per ovary;

style 0.1–0.5 mm.
Seeds

(pale brown), ovoid, 0.9–1.3 × 0.6–0.9 mm.

ovoid, 1–1.2 × 0.6–0.8 mm.
2n

= 80.

= 64.

Draba alpina

Draba macounii
Phenology Flowering Jun–Aug. Flowering Jun–Aug.
Habitat Moist tundra and ridges, sand and gravel flats or beaches Rock outcrops, talus, tundra
Elevation 0-1000 m (0-3300 ft) 700-2800 m (2300-9200 ft)
Distribution
from FNA
LB; MB; NU; ON; QC; Greenland; Europe (Finland, Norway, Russia, Sweden)
[WildflowerSearch map]
[BONAP county map]
from FNA
AK; MT; AB; BC; YT
[BONAP county map]
Discussion

The synonymy above includes two North American names overlooked by C. L. Hitchcock (1941) and R. C. Rollins (1993). Draba alpina was broadly delimited by O. E. Schulz (1927) and included 17 varieties, some of which (e.g., corymbosa, oxycarpa, pilosa) are recognized herein as distinct species. The name D. alpina was so misapplied that it was used for any circumpolar or alpine, scapose, yellow-flowered, perennial Draba. Various chromosome numbers (e.g., 2n = 64, 80, 112, 120; S. I. Warwick and I. A. Al-Shehbaz 2006) have been reported for the species. As circumscribed here, it has the narrow distribution outlined above and includes plants with 2n = 80. Reports of the species from Alaska, Canadian Northwest Territories and Yukon, Siberia, eastern Asia, Russian Far East, and the Central Asian republics are either suspect or very unlikely. The entire D. alpina complex (including the above three species, D. glacialis Adams, D. macounii, etc.) is in need of critical molecular, cytological, and morphological study.

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

Draba macounii is often confused with the circumpolar decaploid (2n = 80) D. alpina. Plants of the former have scapes (0.6–)1–4(–6) cm, fruiting pedicels divaricate to horizontal, gently curved, and 1.5–4.5(–6) mm, and petals pale yellow, spatulate, and 2.7–4 × 1–2 mm. By contrast, D. alpina has scapes (3–)5–17(–28) cm, fruiting pedicels divaricate-ascending to ascending, often straight, and (3–)4–14(–30) mm, and petals bright yellow, obovate, and 3.5–5 × 1.7–2.5 mm. R. C. Rollins (1993) indicated that the species occurs in Colorado, but we have not seen any material from that state.

(Discussion copyrighted by Flora of North America; reprinted with permission.)
Source FNA vol. 7, p. 290. FNA vol. 7, p. 318.
Parent taxa Brassicaceae > tribe Arabideae > Draba Brassicaceae > tribe Arabideae > Draba
Sibling taxa
D. abajoensis, D. albertina, D. aleutica, 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. 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. 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. hydeana, D. alpina var. inflatisiliqua
Name authority Linnaeus: Sp. Pl. 2: 642. (1753) O. E. Schulz: in H. G. A. Engler, Pflanzenr. 89[IV,105]: 97. (1927)
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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