Flora of North America species comparison

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Draba trichocarpa

Draba verna

stanley creek Draba

common Draba, common whitlow-grass, early witlow grass, nailwort, shadflower, spring Draba, spring whitlow-grass, spring whitlow-mustard, vernal whitlow grass, whitlow grass, whitlow wort
Habit Perennials; (cespitose, densely pulvinate); caudex branched (covered with persistent leaves, branches sometimes terminating in sterile rosettes); scapose. Annuals; scapose.
Stems

unbranched, 0.07–0.35 dm, pubescent throughout, trichomes (soft), stalked, subdendritic, (somewhat crisped), 0.1–0.5 mm, (simple ones absent).

(few to many from base), unbranched, (0.2–)0.5–2(–3) dm, pubescent proximally, glabrous distally, trichomes simple and 2(–4)-rayed, 0.1–0.4 mm.
Basal leaves

(densely imbricate); rosulate;

sessile;

blade oblong to obovate, 0.2–0.4 cm × 0.5–1.5 mm, margins entire, (ciliate, trichomes simple and branched, subdendritic, or spurred, 0.3–0.8 mm), surfaces sparsely pubescent, abaxially with stalked, 4–6-rayed stellate trichomes, 0.1–0.4 mm, adaxially with simple and 4–6-rayed trichomes, mainly on distal 1/2.

rosulate;

petiolate;

blade obovate, spatulate, oblanceolate, lanceolate, oblong, or, rarely, linear, 0.2–1.8(–3) cm × (0.5–)1–5(–10) mm, margins entire or 1–5-toothed on each side, surfaces pubescent with simple or stalked, 2–4-rayed trichomes, 0.1–0.5 mm.
Cauline leaves

0 (or 1);

sessile;

blade similar to basal.

0.
Racemes

2–9-flowered, ebracteate, slightly elongated in fruit;

rachis not flexuous, pubescent as stem.

4–20(–30)-flowered, ebracteate, usually considerably elongated in fruit;

rachis usually flexuous, glabrous.
Flowers

sepals ovate, 2–3 mm, pubescent, (trichomes short-stalked);

petal color unknown, broadly obovate, 2–4 × 2–2.5 mm;

anthers oblong, 0.5–0.6 mm.

sepals (green or purplish), oblong, 1–2.5 mm, glabrescent or pubescent, (trichomes simple or 2-rayed);

petals white, deeply 2-fid, (1.5–)2–4.5(–6) × 1–2 mm;

anthers ovate, 0.2–0.4 mm.
Fruiting pedicels

divaricate-ascending to ascending, straight, 1–4.5 mm, pubescent as stem.

divaricate to ascending, straight or slightly curved upward, (2–)5–20(–35) mm, glabrous.
Fruits

ovoid, plane, slightly inflated basally, flattened distally, 2–6 × 2–3.5 mm;

valves densely pubescent, trichomes 4-rayed, 0.1–0.4 mm, (often some rays spurred or branched);

ovules 4–10 per ovary;

style 0.3–0.7 mm.

obovate, oblanceolate, lanceolate, elliptic, oblong, or linear, plane, flattened, (2.5–)4–9(–12) × 1.5–2.5(–3.5) mm;

valves glabrous;

ovules (20–)32–70(–84) per ovary;

style 0.02–0.2 mm.
Seeds

oblong, 1.4–2 × 0.8–1.2 mm.

ovoid (slightly flattened), 0.3–0.6(–0.8) × 0.2–0.4 mm.
2n

= 14, 16, 20, 24, 28, 30, 32, 34, 36, 38, 40, 52, 54, 58, 60, 64.

Draba trichocarpa

Draba verna
Phenology Flowering Jun–Jul. Flowering Feb–May.
Habitat Gravelly metamorphic soil at ecotone between sagebrush steppe and open conifer forests Cedar glades, lawns, fields, pastures, waste places, grassy hillsides, disturbed sites, roadsides
Elevation ca. 2000 m (ca. 6600 ft) 0-2500 m (0-8200 ft)
Distribution
from FNA
ID
[BONAP county map]
from FNA
AL; AR; CA; CT; DC; DE; GA; IA; ID; IL; IN; KY; MA; MD; ME; MI; MO; MS; MT; NC; NH; NJ; NV; NY; OH; OR; PA; RI; SC; TN; UT; VA; VT; WA; WV; WY; AB; BC; NB; ON; QC; Europe; Asia; nw Africa [Introduced in North America; introduced also in Central America, South America, Australia]
[WildflowerSearch map]
[BONAP county map]
Discussion

Of conservation concern.

Draba trichocarpa is an apomictic polyploid that appears to be closely related to D. novolympica. It is readily distinguished from that species by the primarily dendritic trichomes (and absence of simple trichomes) on the stems, pedicels, and fruits. Draba trichocarpa is known from the Stanley Basin of central Idaho (Custer County).

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

Draba verna represents a highly variable and taxonomically difficult complex within which species, subspecies, varieties, and forms have been named (O. E. Schulz 1927); only those synonyms pertaining to North America are listed above. Most of the taxonomic difficulties are the results of disploidy, autogamy, and hybridization. The morphological extremes are connected by intermediate forms in every conceivable character. Furthermore, there appears to be no correlation between morphology, cytology, geography, and ecology to support the division of this complex into meaningful taxa. A complex cytological picture was presented by Ø. Winge (1940), including the highest count of 2n = 94, which has not been confirmed by subsequent botanists.

Erophila vulgaris de Candolle is an illegitimate name for Draba verna.

(Discussion copyrighted by Flora of North America; reprinted with permission.)
Source FNA vol. 7, p. 344. FNA vol. 7, p. 345.
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. 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. 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. 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. viridis, D. weberi, D. yukonensis, D. zionensis
Synonyms D. boerhaavii, D. praecox, D. verna var. aestivalis, D. verna var. boerhaavii, Erophila boerhaavii, Erophila krockeri, Erophila praecox, Erophila verna, Erophila verna subsp. praecox
Name authority Rollins: Contr. Gray Herb. 214: 4. (1984) Linnaeus: Sp. Pl. 2: 642. (1753)
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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