Capsella bursa-pastoris, shepherd's purse

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Intermountain Flora
Annual or winter annual, 1-4 (6) dm tall, from a taproot; herbage with pubescence of small stellate hairs mixed with simple hairs, glabrate to glabrous above; stems erect, simple or branched; leaves basal and cauline, the basal and lower cauline leaves 1-2 cm long, 4-25 mm wide, oblanceolate, tapering into a winged petiole, obtuse apically, toothed to deeply pinnatifid, the cauline leaves lanceolate to linear, sessile, sagittate-clasping, acute apically, shallowly dentate or the uppermost entire; raceme many-flowered, simple or branched, glabrate to glabrous; sepals 1-2 mm long, ovate, obtuse, soon deciduous, greenish, often with a reddish tinge, the margins scarious, sometimes whitish apically petals 2-3 mm long, clawed, oblanceolate to spatulate, white; fruiting pedicels 7-20 (27) mm long, widely spreading; silicles 4.5-6 (8) mm long, 3-5 mm wide, obtriangular, cuneate basally, slightly retuse to truncate apically, strongly flattened at right angles to the plane of the septum, the valves glabrous, the midnerve forming a prominent keel; mature stlye short, 0.3-0.5 mm long, persistent, the stigma small, capitate; seeds numerous, 0.8-1 mm long, oblong, finely alveolate, brown, the cotyledons incumbent; 2n = 16, 32.

Cronquist, A., Holmgren, N.H., and Holmgren, P.K. (2005) "Intermountain Flora" pg. 270, vol. 2 part B, The New York Botanical Garden New York.