24. Cardamine micranthera Rollins, Castanea. 5: 87. 1940.
Perennials; glabrous throughout. Rhizomes (relatively short), 2-3 mm diam., (covered with extensive root system). Stems erect to ascending, unbranched or branched distally, 0.9-4 dm. Rhizomal leaves usually 3-foliolate, rarely simple, 1-8 cm, leaflets petiolulate or subsessile; petiole 0.5-5 cm; lateral leaflets subsessile, often minute; terminal leaflet (petiolule 0.4-2 cm), blade orbicular to broadly ovate, 0.5-3 cm × 5-25 mm, base rounded, margins entire, repand, or dentate. Cauline leaves 5-10, petiolate; middle leaves often simple, petiole 0.3-1.5 cm, blade rhombic to suborbicular or ovate, 1-3.5 cm × 6-22 mm, base obtuse to cuneate, margins entire, repand, or dentate; distal ones with shorter petiole, blade smaller. Racemes ebracteate. Fruiting pedicels divaricate, 9-17 mm. Flowers: sepals (ascending), oblong, 1.5-2.2 × 0.7-1 mm, lateral pair not saccate basally; petals (somewhat spreading), white, oblanceolate, 3.5-5 × 1.2-1.8 mm, (not clawed, apex rounded); filaments: median pairs 2.5-3 mm, lateral pair 2-2.5 mm; anthers ovate, ca. 0.2 mm. Fruits linear, 0.8-1.6 cm × 0.8-1 mm; ovules 16-22 per ovary; style 1.2-1.8 mm. Seeds brown, oblong to ovoid, 0.9-1.2 × 0.6-0.8 mm.
Flowering Apr-May. Wet grounds along streams, seepage, gravelly sandbars, moist crevices; of conservation concern; N.C.
Cardamine micranthera is known only from Stokes County. It is in the Center for Plant Conservation’s National Collection of Endangered Plants.