ALYSSUM L., Sp. Pl. 2: 650 (1753).

Herbs annual, biennial, or perennial with caudex, rarely subshrubs. Trichomes sessile, 6–24-rayed stellate, rarely mixed with simple or forked ones on fruit, very rarely lepidote scales. Multicellular glands absent. Stems erect to ascending or decumbent, leafy, not spiny. Basal leaves petiolate, rosulate or not, simple, entire; cauline leaves petiolate or sessile, cuneate to attenuate, not auriculate at base, entire. Racemes few to many flowered, ebracteate, corymbose, elongated in fruit; rachis straight; fruiting pedicels erect, ascending, divaricate, or reflexed, persistent. Sepals ovate to oblong, free or appearing united due to interlocking trichomes, deciduous or persistent, erect to ascending, equal or rarely unequal, base of lateral pair not saccate; petals yellow, white, or purple-tinged at least proximally, erect throughout or with flaring blade or ascending, subequaling or longer than sepals; blade obovate, spatulate, oblong, or oblanceolate, apex obtuse, retuse, or emarginate; claw distinct or undifferentiated from blade, shorter than sepals, glabrous, unappendaged, entire; stamens 6, exserted or included, erect to ascending, subequal or tetradynamous; filaments wingless and slender or uni- or bilaterally winged, toothed or toothless, appendaged or not, glabrous, free or rarely inner 4 connate in 2 pairs; anthers ovate or oblong, not apiculate; nectar glands 4, lateral, 1 on each side of lateral stamen, median glands absent; ovules 4 per ovary; placentation subapical. Fruit dehiscent, capsular silicles, oblong, ovate, obovate, ovoid, elliptic, or orbicular, latiseptate, unilaterally inflated or not inflated, unsegmented; valves papery, veinless, glabrous or pubescent, not keeled, smooth, wingless, unappendaged; gynophore absent or obsolete; replum rounded, visible; septum complete, membranous, veinless; style 0.5–3 mm long, filiform, persistent; stigma capitate, entire, unappendaged. Seeds aseriate, winged or wingless, ovate, flattened; seed coat mucilaginous or not when wetted; cotyledons accumbent.