Perennials. Rootstock ± vertical, 8-9 mm in diam., not tuberculate, with a fascicle of long thickened roots. Stem 49-89 cm tall, erect, not rooting at nodes, with 0.2-0.5 mm retrorse appressed nonglandular trichomes. Stipules lanceolate, connate at least at base. Leaves opposite; petiole with 0.2-0.5 mm retrorse appressed nonglandular trichomes; leaf blade 4.1-9.5 cm, palmately cleft, ratio of main sinus/middle segment length = 0.89-0.96, pilose with appressed nonglandular trichomes; segments 5, rhombic, 1.6-4.4 mm wide at base, 8-18-lobed in distal half, ratio of second sinus/middle segment length = 0.3-0.58. Cymules solitary, 2-flowered; peduncle 4.7-10.4(-13.7) cm. Pedicel 1.1-4.1 cm, with 0.2-0.6 mm retrorse appressed or rarely patent nonglandular trichomes; bracteoles lanceolate. Sepals 7.3-10.8 mm, mucro 1.2-2.5 mm, ratio of mucro/sepal length = 0.13-0.26, outside with 0.2-0.4 mm antrorse appressed nonglandular trichomes, inside glabrous. Petals deep reddish purple, (1.3-)1.4-1.8(-2) cm, erect to patent, outside basally with trichomes, inside basal 1/3-1/2 with trichomes, margin basally ciliate, apex rounded. Staminal filaments purplish, lanceolate, base slightly dilated, abaxially pilose and proximal half ciliate, trichomes 0.2-0.6 mm; anthers bluish, 1.5-2.3 mm. Nectaries 5, hemispheric, with a tuft of trichomes at apex, abaxially glabrous. Stigma reddish. Fruit 2.8-3.5 cm, erect when immature; mericarps smooth, with a basal callus, with 0.1-0.7 mm ± patent nonglandular trichomes and sometimes apically with 0.7-1.1 mm patent glandular trichomes; rostrum 1.8-2.3 cm, with a 1.9-3.4 mm narrowed apex; stigmatic remains 5-6.7 mm. Seeds 2.3-2.6 mm. Fl. Jul-Aug, fr. Aug-Sep. 2n = 28.