28. Rapistrum Crantz, Cl. Crucif. Emend. 105. 1769.
Wild-turnip, turnipweed [Latin rapa, turnip, and -astrum, incomplete resemblance]
Suzanne I. Warwick
Annuals [perennials] ; not scapose; glabrous or pubescent. Stems erect, unbranched or branched basally. Leaves basal and cauline; petiolate or subsessile; basal not rosulate, petiolate, blade margins usually pinnate to lyrately pinnatifid, rarely undivided, dentate; cauline subsessile or shortly petiolate, blade (base not auriculate), margins lobed, subentire, or dentate. Racemes (corymbose, several-flowered), greatly elongated in fruit. Fruiting pedicels erect [ascending], (usually appressed to rachis), slender to stout. Flowers: sepals ascending, oblong, lateral pair not saccate basally, (hispid [glabrous or with subapical tuft of hairs]); petals yellow, obovate, claw differentiated from blade, (apex ± truncate); stamens tetradynamous; filaments not dilated basally; anthers ovate to suboblong, (apex obtuse); nectar glands confluent, median glands present. Fruits silicles, indehiscent, sessile, segments 2, elliptic to oblong, torulose, (slightly to strongly constricted at transverse joint), terete or angular; (valvular segment persistent, dehiscent [indehiscent], 1(-3)-seeded, longitudinally striate or smooth, occasionally seedless and nearly as wide as pedicel; terminal segment indehiscent, caducous at maturity, usually 1-seeded, rarely seedless); valves glabrous or pubescent; septum complete; ovules 2-4; (style persistent, filiform); stigma capitate, (flattened), 2-lobed. Seeds uniseriate, slightly compressed, not winged, ovoid [oblong]; seed coat (smooth), not mucilaginous when wetted; cotyledons conduplicate. x = 8.
Species 2 (1 in the flora): introduced; s Europe (Mediterranean region); introduced also nearly worldwide.