STENOPETALUM R. Brown ex de Candolle, Syst. Nat. 2 : 513. 1821.
Ihsan A. Al-Shehbaz
Name derivation: Greek stenos, narrow, and petalon, petals, in reference to the narrow petals.
Type species: Stenopetalum lineare R. Brown ex de Candolle.
Herbs, annual or perennial, rarely subshrubs or shrubs. Trichomes absent or simple, malpighiaceous, stellate, or dendritic. Multicellualr glands absent. Stems erect, ascending, or decumbent, often branched at least above. Basal leaves early caducous, petiolate, not rosulate, simple, pinnately dissected; cauline leaves petiolate or subsessile, cuneate to attenuate, not auriculate, entire, trisect, or pinnatisect. Racemes several or many flowered, ebracteate, lax, elongated considerably in fruit; rachis straight; fruiting pedicels erect to divaricate or strongly reflexed, rarely geniculate at base, persistent. Sepals ovate to oblong, free, deciduous, erect, subequal, base of lateral pair saccate or not. Petals white, orange, brown, olive-green, or rarely purplish, erect at base with spreading blade, much longer than sepals; blade filiform, linear to narrowly lanceolate, apex acute; claw strongly differentiated from blade, subequaling sepals, glabrous, unappendaged, entire. Stamens 6, included, erect, tetradynamous; filaments wingless, unappendaged, glabrous, free; anthers ovate to oblong, not apiculate. Nectar glands lateral and 1 on each side of lateral stamens, sometimes annular; median glands present or absent. Ovules 8-40 per ovary; placentation parietal. Fruit dehiscent capsular silicles, globose, ellipsoid, ovoid, or obovoid, terete or latiseptate, not inflated, unsegmented; valves papery, veinless, glabrous, smooth, wingless, unappendaged; gynophore obsolete; replum rounded, visible; septum complete, membranous, veinless; style obsolete or to 0.5 mm, persistent; stigma capitate, entire, unappendaged. Seeds biseriate, wingless, oblong to ellipsoid, flattened; seed coat smooth, copiously mucilaginous when wetted; cotyledons incumbent or accumbent. x = 4, 5.
Twelve species: Australia.
References: Keighery (2002), Shaw (1972).
See interactive key to the species