CUPHONOTUS O. E. Schulz, Bot. Jahrb. Syst. 66: 92. 1933.
Ihsan A. Al-Shehbaz
Name derivation: from Greek cuphos, Light weight, and notus, back, in reference to the poorly developed keel or the valve back.
Herbs annual. Trichomes absent or simple, usually crisped. Multicelluar glands absent. Stems erect to decumbent, branched. Basal leaves subpetiolate, subfleshy, not forming a rosette, simple, entire or shallowly pinnatifid; cauline leaves subsessile and cuneate to attenuate, not auriculate at base, entire, dentate, or pinnatifid. Racemes many-flowered, ebaracteate, corymbose, elongated considerably in fruit; rachis straight; fruiting pedicels divaricate, persistent. Sepals oblong to elliptic, free, deciduous, spreading, equal, base of inner pair not saccate; petals white or creamy white, spreading, longer to subequaling sepals; blade oblanceolate to linear, apex obtuse, margin obscurely lobed; claw obscurely distinct from blade, shorter than sepals, glabrous, unappendaged, entire; stamens 6, exserted, spreading, tetradynamous; filaments wingless, unappendaged, glabrous, free, dilated at base; anthers ovate, rounded at base, obtuse at apex; nectar glands 4, distinct; median nectaries absent; lateral nectaries 1 on each side of lateral stamens; ovules 2-15 per ovary; placentation parietal. Fruit dehiscent, capsular silicles, ovoid, ellipsoid, to subglobose, slightly angustiseptate, not inflated, sessile, unsegmented; valves subleathery, veinless or prominently veined, glabrous, not keeled and rounded, smooth, wingless, unappendaged; gynophore absent; replum rounded; septum complete, membranous, without a midvein; style obsolete or short and less than 1 mm long, stout, persistent, glabrous; stigma capitate, entire or slightly 2-lobed, unappendaged. Seeds uniseriate, margined, ellipsoid, sligtly flattened; seed coat smooth, copiously mucilaginous when wetted; cotyledons incumbent, entire.
Two species; Australia.
Reference: Shaw (1974).