34. Capsella Medikus, Pfl.-Gatt. 85. 1792.
Shepherd’s-purse [Latin capsa, box or case, alluding to fruit resembling medieval wallet or purse]
Ihsan A. Al-Shehbaz
Bursa Boehmer; Rodschiedia P. Gaertner, B. Meyer & Scherbius; Solmsiella Borbás
Annuals or biennials; not scapose; mostly pubescent, trichomes sessile and stellate, sometimes mixed with simple or forked ones. Stems erect or ascending, unbranched or branched. Leaves basal and cauline; petiolate or sessile; basal rosulate, petiolate, blade margins pinnately lobed, lyrate, runcinate, or, rarely, entire, dentate, or repand [sinuate]; cauline blade (base sagittate, amplexicaul, or auriculate), margins entire, dentate, or sinuate. Racemes (corymbose, several-flowered), considerably elongated in fruit. Fruiting pedicels divaricate, slender. Flowers: sepals erect or ascending, [ovate-]oblong, (glabrous or pubescent); petals [sometimes absent] usually white or pink [reddish], obovate [spatulate], (much longer or shorter than sepals), claw differentiated from blade, (apex obtuse); stamens tetradynamous; filaments not dilated basally; anthers ovate [oblong], (apex obtuse); nectar glands (4), lateral, 1 on each side of lateral stamen. Fruits silicles, dehiscent, sessile, obdeltoid to obdeltoid-obcordiform, strongly flattened, strongly keeled, angustiseptate; valves (papery), each prominently veined, glabrous; replum rounded; septum complete; ovules (12-)20-40 per ovary; (style included or exserted from apical notch); stigma capitate. Seeds uniseriate, plump, not winged, oblong; seed coat (reticulate), mucilaginous when wetted; cotyledons incumbent. x = 8.
Species 4 (1 in the flora): introduced; Europe, Asia, n Africa; introduced also in Mexico, West Indies, Central America, South America, Atlantic Islands, Pacific Islands, Australia.
SELECTED REFERENCES Hurka, H. and B. Neuffer. 1997. Evolutionary processes in the genus Capsella (Brassicaceae). Pl. Syst. Evol. 206: 295-316. Neuffer, B. and H. Hurka. 1999. Colonizing history and introduction dynamics of Capsella bursa-pastoris in North America: Isozymes and quantitative traits. Molec. Ecol. 8: 1667-1681. Nutt, P. et al. 2006. Capsella as a model system to study the evolutionary relevance of floral homeotic mutants. Pl. Sys. Evol. 259: 217-235. Slotte, T. et al. 2006. Intrageneric phylogeny of Capsella (Brassicaceae) and the origin of the tetraploid C. bursa-pastoris based on chloroplast and nuclear DNA sequences. Amer. J. Bot. 93: 1714-1724.