IODANTHUS (Torrey & A. Gray) Steudel, Nom. Bot., ed. 2, 1: 812. 1840.

Ihsan A. Al-Shehbaz

Tribe: Cardamineae Dumort., Fl. Belg.: 124. 1827.

Name derivation: Greek iodes, violet colored, and anthos, flower.

Type species: Iodanthus pinnatifidus (Michaux) Steudel (based on Hesperis pinnatifida Michaux).

Note: although Iodanthus Torrey & A. Gray [Fl. N. Amer. 1: 72. 1938] was a validly published name, it was unranked and, therefore, its validation as a generic names dates from Steudel’s publication.

Herbs, perennial. Trichomes simple or absent. Multicellular glands absent. Stems erect, branched above. Basal leaves petiolate, not rosulate, lobed or not, withered by flowering time; cauline leaves with winged petioles or uppermost sessile, auriculate, simple, dentate or entire, lowermost sometime lyrately lobed. Racemes many-flowered, ebracteate, lax, elongated considerably in fruit; rachis straight; fruiting pedicels divaricate to ascending, persistent, slender or stout. Sepals oblong, free, caducous, erect to ascending, equal, base of lateral pair not or slightly saccate. Petals purple, pink, or white, erect at base with flaring blade, longer than sepals; blade spatulate, obtuse; claw differentiated from balde, subequaling sepals, glabrous, unappendaged, entire. Stamens 6, slightly exsertd, tetradynamous; filaments wingless, unappendaged, glabrous, free; anthers linear to narrowly oblong, apex apiculate. Nectar glands confluent, lateral glands annular; median glands present. Ovules 22–36 per ovary, placentation parietal. Fruits dehiscent siliques, linear, terete, not inflated, unsegmented; valves papery, with a distinct midvein, glabrous, not keeled, smooth, wingless; gynophore obsolete; replum rounded, visible; septum complete, membranous, not veined; style distinct, to 4 mm, persistent; stigma capitate, entire, unappendaged. Seeds uniseriate, wingless, oblong, plump; seed coat minutely reticulate, not mucilaginous when wetted; cotyledons accumbent.

Monospecific: E and C United States.

References: Dvořák (1970), Price & Al-Shehbaz (2001), Rollins (1942).