Iodanthus

Perennials; not scapose; glabrous or sparsely pubescent. Stems erect, branched distally. Leaves basal and cauline; petiolate or sessile; basal (withered by flowering), not rosulate, petiolate, blade margins lobed or not; cauline petiolate (petioles winged) or sessile, blade (base auriculate), margins dentate, entire, or lyrately lobed. Racemes (lax), considerably elongated in fruit. Fruiting pedicels divaricate to ascending, slender or stout. Flowers: sepals erect to ascending, oblong, lateral pair not or slightly saccate basally; petals purple, pink, or white, spatulate, (longer than sepals), claw differentiated from blade; stamens tetradynamous; filaments not dilated basally; anthers linear to narrowly oblong, (apiculate); nectar glands: lateral annular, median glands confluent with lateral. Fruits siliques, sessile or shortly stipitate, linear, smooth, terete; valves each with distinct midvein, glabrous; replum rounded; septum complete; ovules 22-36 per ovary; style distinct; stigma capitate. Seeds uniseriate, plump, not winged, oblong; seed coat (minutely reticulate), not mucilaginous when wetted; cotyledons accumbent.

R. C. Rollins (1993) recognized four species in Iodanthus, of which three are endemic to Mexico. As summarized by R. A. Price and I. A. Al-Shehbaz (2001), molecular data clearly support treatment of the genus as monospecific and closely allied to Cardamine, as well as recognition of the three Mexican species as members of Chaunanthus, a genus unrelated to Iodanthus and members of the Thelypodieae.

Sep erect, the inner somewhat saccate at base; pet pale violet to nearly white, the blade triangular-obovate, gradually narrowed to the exsert claw; short stamens surrounded at base by an annular gland; anthers linear-oblong; ovary cylindric; style short, scarcely differentiated; stigma capitate; frs linear, terete or nearly so, short-beaked, slightly constricted below the seeds; valves with an inconspicuous midnerve; seeds numerous, in 1 row. 4, N. Amer.

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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