Annuals (winter); scapose; glabrous. Stems (sometimes absent), decumbent, branched basally and distally. Leaves basal and, sometimes, cauline; petiolate; basal rosulate, blade margins entire or lyrate-pinnatifid; cauline blade (base not auriculate), margins entire or lyrate-pinnatifid, (similar to basal). Inflorescences usually solitary flowers (on long peduncles from basal rosettes), sometimes racemes present in robust plants (corymbose, several-flowered), elongated in fruit. Flowers: sepals spreading or suberect, oblong or oblong-linear, lateral pair not saccate basally; petals white, lavender, orange, or yellow, obovate to spatulate, obcordate, or oblanceolate, (much longer than sepals), claw differentiated from blade, (much shorter than blade, apex shallowly to deeply emarginate or, rarely, truncate or obtuse); stamens strongly tetradynamous, (erect); filaments not dilated basally; anthers oblong, (apex obtuse); nectar glands: lateral annular, median glands present (distinct). Fruits siliques or silicles, sessile or shortly stipitate, linear to oblong or subglobose, torulose or smooth (or submoniliform), latiseptate, subterete, or terete; valves each obscurely veined; replum rounded; septum complete; ovules 5-25 per ovary; style distinct, (slender or stout); stigma capitate, (sometimes slightly 2-lobed). Seeds uniseriate, flattened, broadly winged or margined, suborbicular; seed coat (prominently reticulate), not mucilaginous when wetted; cotyledons obscurely accumbent, (radicle much shorter than cotyledon, straight or slightly bent). x = 11, 12, 15.
Sep obtuse, erect to spreading; pet white to anthocyanic or yellow, narrowly spatulate-obovate to lingulate, retuse to truncate; ovary cylindric, with a short, stout, scarcely differentiated style and capitate stigma; frs typically linear to oblong and compressed parallel to the septum, but varying to terete or subglobose; valves reticulately veined, the midnerve evident only near the base; seeds in a single row, flattened, evidently winged to virtually wingless; racemes arising from the base of the pl, either reduced to a single long-pedicellate fl (seemingly on a scape), or with a short rachis scarcely surpassing the basal lvs and bearing a few long pedicels; small, glabrous winter-annuals of thin, vernally wet, summer-dry soil in calcareous cedar-glades, and now also in disturbed habitats, as along roadsides, blooming in early spring, the earliest lvs simple, the others lyrate-pinnatifid. 7, c. and sc. U.S.A.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
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