Draba

Annuals, biennials, or perennials [subshrubs]; (caudex simple or branched); scapose or not; glabrous or pubescent, trichomes stalked or sessile, simple, forked, cruciform, stellate, malpighiaceous, or dendritic, often more than 1 kind present. Stems usually erect to ascending, sometimes decumbent or prostrate, unbranched or branched (usually distally). Leaves usually basal and cauline, sometimes cauline absent; petiolate or sessile; basal usually rosulate, usually petiolate, rarely sessile, blade margins usually entire or toothed, rarely pinnately lobed; cauline (when present), petiolate or sessile, blade (base cuneate [auriculate]), margins entire or dentate. Racemes (often corymbose, sometimes bracteate), elongated or not in fruit. Fruiting pedicels (proximalmost) erect or ascending to divaricate, slender. Flowers: sepals (rarely persistent), erect, ascending, or, rarely, spreading, ovate or oblong [elliptic], lateral pair not saccate or subsaccate basally; petals (erect or ascending to patent), yellow, white, pink, purple, or orange [red], obovate, spatulate, oblanceolate, or linear [orbicular, oblong], (longer than or, rarely, shorter than sepals), claw obscurely to well-differentiated from blade, (apex obtuse, rounded, notched, or, rarely, deeply 2-lobed); stamens slightly to strongly tetradynamous; filaments dilated or not basally, (glabrous); anthers ovate or oblong, (not apiculate); nectar glands (1, 2, or 4), distinct or confluent, subtending bases of stamens, median glands present or absent. Fruits silicles or siliques, sessile, ovate, lanceolate, elliptic, oblong, linear, suborbicular, ovoid, or subglobose, plane or spirally twisted, smooth, (not keeled, unappendaged), usually latiseptate, rarely terete; valves (papery), each with distinct or obscure midvein and lateral veins, glabrous or pubescent; replum rounded; septum complete; ovules 4-70(-88) per ovary; style obsolete or distinct; stigma capitate. Seeds biseriate, oblong, ovate, or orbicular, usually flattened (slightly flattened in D. aleutica, D. verna), usually not winged (winged in D. asterophora, D. brachycarpa, D. carnosula, D. pterosperma); seed coat (minutely reticulate), not mucilaginous when wetted; cotyledons accumbent. x = 6-12.

Sep ascending or erect, blunt; pet yellow or white, rounded, emarginate, or rarely bifid, narrowed below to a claw, or in some spp. reduced or wanting; anthers short, oval or oblong; ovary ovoid, with 2-many ovules per locule; style short or none; stigma capitate; glands various; fr a silicle, seldom 5 times as long as wide; herbs with entire to dentate lvs, the hairs simple to branched or stellate. 350, mostly cool N. Hemisphere, 65 in S. Amer.

Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.

©The New York Botanical Garden. All rights reserved. Used by permission.