Asarum geophilum Hemsl.

This species is used medicinally, known as 土细辛 (tu xi xin).

Herbs. Rhizomes horizontal, 3-4 mm in diam., internodes 0.5-1.5 cm. Leaves paired; petiole 3-15 cm, villous; leaf blade uniformly colored, orbicular-cordate, ovate-cordate, or broadly ovate, 5-10 × 5.5-12.5 cm, abaxial surface densely yellow-brown pubescent or glabrescent, adaxial surface sparsely pubescent or glabrous, apex acute or obtuse; cataphylls ovate or narrowly ovate, ca. 0.8 × 0.4 cm. Peduncle declinate, 0.5-1.5 cm. Calyx slightly zygomorphic, purplish, subrotate, 1.5-2 × 2-2.5 cm; sepals connate beyond attachment to ovary, abaxially pubescent, adaxially dark red pubescent; tube obconic, ca. 0.5 × 0.6-1 cm; lobes spreading, triangular-orbicular, ca. 0.8 × 1-1.2 cm. Stamens 12; filaments less than 0.4 mm, shorter than anthers; anthers 2-3 mm; connectives extended beyond anthers, subcylindric, 0.7-1.3 mm. Ovary inferior. Styles connate, short and thick, apex 6-cleft; stigmas terminal, radiating downward, decurrent. Fl. Apr-Jun.

Guangdong, Guangxi, S Guizhou.

* Dense forests, moist valleys; 200-700 m.

Asarum cavaleriei H. Léveillé & Vaniot; A. cavaleriei var. esquirolii Léveillé; A. taiwanense S. S. Ying; Geotaenium geophilum (Hemsley) F. Maekawa, comb. inval.