DIPTYCHOCARPUS Trautvetter, Bull Soc. Impe. Naturatlistes Moscou 33: 108. 1860.
Ihsan A. Al-Shehbaz
Tribe: Chorisporeae Ledebour, C.A. Meyer & Bunge, Fl. Altaic. 3: 104. 1831.
Name derivation: from Greek dis, two, ptychos, fold or groove, and carpus, fruit, in reference to the groves between seeds on both sides of the fruit.
Type species: Diptychocarpus strictus (Fischer ex Bieberstein) Trautvetter (based on Raphanus strictus Fischer ex Bieberstein.
Alloceratium J. D. Hooker & Thomson, J. Proc. Linn. Soc., Bot. 5: 135. 1861. Type species: A. strictum (Fischer ex Bieberstein) J. D. Hooker & Thomson (based on Raphanus strictus Fischer ex Bieberstein.
Orthorrhiza Stapf, Denkschr. Akad. Wiss. Wien Math.-Nat. Kl. 51: 306. 1886. Type species: O. persica Stapf.
Herbs annual. Trichomes simple. Multicellular glands present, multiseriate. Stems erect, simple basally, often branched above. Basal leaves petiolate, not rosulate, simple, sinuate-dentate to dentate or rarely pinnatisect; cauline leaves similar to basal ones, uppermost entire, subsessile. Racemes ebracteate, few flowered, lax, elongated considerably in fruit; rachis slightly flexuous; fruiting pedicels thickened, terete, ascending to subdivaricate. Sepals oblong-linear, free, connivent, deciduous, erect, unequal, base of inner pair saccate. Petals purple to whitish, erect at base with flaring blade, longer than sepals; blade linear-oblanceolate, apex obtuse; claw obscurely differentiated from blade, glabrous, unappendaged, entire. Stamens 6, included, erect, tetradynamous; filaments filiform, wingless, unappendaged, not dilated at base, glabrous, free; anthers ovate, not or apiculate at apex. Nectar glands 4, lateral, 1 on each side of lateral stamens; median glands absent. Ovules 10-40 per ovary; placentation parietal. Fruit dimorphic siliques, linear, torulose, glabrous, wingless, unappendaged; lowermost fruit indehiscent, terete, breaking into 1-seeded units, corky; upper fruit capsular, dehiscent, latiseptate, unsegmented, with obscurely veined leathery valves; gynophore absent; replum rounded; septum corky in lower fruits, opaque in upper ones, complete, and veinless; style to 8 mm, stout, cylindric to subconical, persistent, glabrous; stigma capitate, 2-lobed, lobes connivent. Seeds uniseriate, broadly winged, oblong to orbicular, strongly flattened; seed coat smooth, not mucilaginous when wetted; cotyledons accumbent.
One species: C and SW Asia.