Flora of North America species comparison

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Draba incerta

Draba pectinipila

whitlow-wort, Yellowstone Draba, Yellowstone Draba whitlow-wort, Yellowstone whitlow-grass, Yellowstone whitlow-wort
Habit Perennials; (cespitose, often pulvinate); caudex branched (dense with persistent leaf remains, branches sometimes terminating in sterile rosettes); scapose. Perennials; (cespitose, sometimes forming mats); caudex branched (with persistent leaf bases, branches creeping, terminating in scapes or sterile rosettes); scapose.
Stems

unbranched, (0.2–)0.4–1.4(–2.1) dm, often pubescent throughout, sometimes glabrous distally, trichomes often simple and 2–5-rayed, 0.1–0.5 mm, (sometimes with mostly subpectinate ones).

unbranched, (0.3–)0.4–1.6(–1.9) dm, pubescent, trichomes sessile, pectinate, 0.1–0.4 mm, (parallel to long axis of stem, sometimes with irregularly 2–4-rayed ones, 0.2–0.6 mm).
Basal leaves

rosulate; petiolate;

petiole (0–1 cm), ciliate throughout;

blade narrowly oblanceolate to linear, (0.4–)0.6–1.7(–2.5) cm × (1–)1.5–3.5(–5) mm, margins entire, (ciliate, trichomes usually simple, rarely 2-rayed, 0.2–1.1 mm), surfaces usually pubescent with short-stalked, pectinate trichomes, 0.15–0.5 mm, sometimes also with 4–6-rayed ones, (midvein usually obscure abaxially), sometimes glabrous adaxially.

rosulate;

subsessile;

blade narrowly oblanceolate to linear, (0.4–)0.6–1.3(–2) cm × 0.9–2.2 mm, margins entire (not ciliate), surfaces pubescent with subsessile or sessile, pectinate trichomes, 0.2–0.5 mm.
Cauline leaves

usually 0 (or 1, as a bract);

sessile;

blade linear to oblong, margins entire, surfaces pubescent as basal.

0.
Racemes

3–14(–30)-flowered, usually ebracteate, rarely proximalmost flowers bracteate, elongated in fruit;

rachis not flexuous, glabrous or pubescent as stem.

5–22-flowered, ebracteate, considerably elongated in fruit;

rachis not flexuous, pubescent as stem.
Flowers

sepals broadly ovate, 2.5–3.5(–4) mm, pubescent, (trichomes simple and 2- or 3-rayed);

petals yellow (fading white), oblanceolate to obovate, 4–6 × 1.5–2.5 mm;

anthers ovate, 0.3–0.5 mm.

sepals broadly ovate, 2–3.2 mm, pubescent, (trichomes pectinate);

petals yellow, obovate to spatulate, 4–6.5 × 1.5–2.5 mm;

anthers ovate 0.4–0.5 mm.
Fruiting pedicels

ascending, straight, (2.5–)4–11(–27) mm, glabrous or pubescent, trichomes 2–5-rayed or pectinate.

divaricate-ascending, straight, (5–)7–14 mm, sparsely pubescent, trichomes pectinate.
Fruits

broadly ovate to lanceolate, plane, flattened, 5–9(–11) × 2–4 mm;

valves glabrous or puberulent, trichomes simple and 2-rayed, 0.05–0.3 mm;

ovules 8–16(–20) per ovary;

style 0.2–0.9 mm.

ovoid, plane, slightly inflated basally, 4–6(–7) × 2–3 mm;

valves pubescent, trichomes usually sessile, pectinate, 0.2–0.5 mm, rarely with simple ones;

ovules 4–8 per ovary;

style 0.5–1.5 mm.
Seeds

oblong, 1.1–1.5 × 0.7–1 mm.

oblong, 1.1–1.5 × 0.6–0.8 mm.
2n

= 112.

= 22.

Draba incerta

Draba pectinipila
Phenology Flowering Jun–Aug. Flowering Apr–Jun.
Habitat Rock outcrops, talus, gravelly areas, tundra Rocky slopes in sagebrush scrub and pinyon-juniper woodlands
Elevation 0-3300 m (0-10800 ft) 1700-2400 m (5600-7900 ft)
Distribution
from FNA
AK; CO; ID; MT; NV; UT; WA; WY; AB; BC; QC; YT
[WildflowerSearch map]
[BONAP county map]
from FNA
CO; MT; UT; WY
[BONAP county map]
Discussion

Draba incerta was shown by G. A. Mulligan (1972) to be sexually reproducing and 14-ploid with x = 8. It is often confused with the apomict D. oligosperma (2n = 32, 64). Draba incerta is readily separated from D. oligosperma by having well-formed (versus abortive) anthers and pollen, stalked (versus sessile) leaf trichomes, and ciliate (versus non-ciliate) basal leaves with obscure (versus prominent) midveins. Although both species have leafless scapes, one often finds a bract adnate to, or subtending, the proximalmost pedicel in D. incerta.

Draba incerta is found near sea level in Alaska.

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

Draba pectinipila was treated as a synonym of D. oligosperma by G. A. Mulligan (1972), R. C. Rollins (1993), and N. H. Holmgren (2005b). The latter recognized D. juniperina as a distinct species but overlooked the fact that it is indistinguishable from the type collections of the earlier-published D. pectinipila. The species (including D. juniperina) differs significantly from D. oligosperma in both chromosome number and morphology. Draba pectinipila is easily distinguished by having fruit valves pubescent with pectinate trichomes, fruiting pedicels (5–)7–14 mm, petals 4–6.5 mm, ovules 4–8 per ovary, and styles 0.5–1.5 mm. By contrast, D. oligosperma has fruit valves glabrous or pubescent with simple or 2-rayed trichomes, fruiting pedicels (2–)3–10(–13) mm, petals 2.5–4 mm, ovules 6–12 per ovary, and styles 0.1–0.8(–1.1) mm. Draba pectinipila was previously known only from the type locality in northwestern Wyoming (Park County). Its range is now expanded to include that of D. juniperina in northwestern Colorado (Moffat County), northeastern Utah (Daggett and Uintah counties), and southwestern Wyoming (Sweetwater County). The record from Uintah County is based on Goodrich 22275 (NY).

(Discussion copyrighted by Flora of North America; reprinted with permission.)
Source FNA vol. 7, p. 313. FNA vol. 7, p. 328.
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. 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. 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. 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. exalata, D. incerta var. laevicapsula, D. incerta var. peasei, D. laevicapsula, D. peasei D. juniperina, D. oligosperma var. juniperina, D. oligosperma var. pectinipila
Name authority Payson: Amer. J. Bot. 4: 261. (1917) Rollins: Rhodora 55: 231. (1953)
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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