PTERYGOSTEMON V.V.Botschantz., Bot. Zhurn. (Moscow & Leningrad) 62: 1504 (1977).

Herbs perennial, canescent throughout, with simple or few-branched caudex terminated in central rosette and without leaf or petioles of previous seasons. Trichomes sessile, 12–20 rayed, stellate, with rigid rays, without webbing, often umbonate at least on leaves, simple trichomes absent. Multicellular glands absent. Stems erect to ascending, originating from below central rosette, leafy, not spiny. Basal leaves petiolate, rosulate, simple, entire, obscurely veined abaxially; cauline leaves petiolate, not auriculate at base, entire. Racemes few to several flowered, ebracteate, corymbose, slightly elongated in fruit; rachis straight; fruiting pedicels ascending to divaricate, straight, densely pubescent, persistent. Sepals oblong, free, deciduous, erect, pubescent, unequal, base of lateral pair slightly saccate; petals yellow, erect at base with flaring blade, longer than sepals; blade oblong, apex obtuse; claw differentiated from blade, subequalling or shorter than sepals, glabrous, unappendaged, entire; stamens 6, exserted, erect, tetradynamous; filaments of median pairs narrowly winged, unappendaged, those of lateral pair slender, wingless, all glabrous, free; anthers oblong, not apiculate; nectar glands 2, lateral, ringlike and surrounding base of lateral stamen, median glands absent; ovules 4–8 per ovary; placentation parietal. Fruit dehiscent, capsular silicles, orbicular to broadly ovate, strongly latiseptate, not inflated, unsegmented; valves thin leathery, veinless, densely pubescent outside, glabrous inside, not keeled, smooth, wingless, unappendaged; gynophore absent; replum rounded concealed by valve margins; septum complete, membranous, veinless; style 1.5–2 mm long, filiform, pubescent along proximal half, caducous; stigma capitate entire, unappendaged. Seeds biseriate, winged all around, broadly ovate to suborbicular, strongly flattened; seed coat not mucilaginous when wetted; cotyledons accumbent.