Pellionia subundulata W. T. Wang var. angustifolia W. T. Wang.

Herbs perennial, dioecious or monoecious. Stems erect, simple, crispately strigose. Leaves alternate; stipules broadly lanceolate, 6-11 × 2.5-4 mm; petiole 1-2.5 mm; leaf blade herbaceous, obliquely elliptic or linear-lanceolate, 6-13 × 2.8-4.5 cm, major lateral veins asymmetric, one basal, the other arising above base, broader outer half auriculate, margin obscurely denticulate, apex caudate-acuminate; cystoliths obscure, sparse; nanophyll absent. Staminate inflorescences 1.4-2 cm in diam., peduncle 5-13 cm; staminate flowers: tepals 5, broadly elliptic; stamens 5; rudimentary pistil nearly triangular. Pistillate inflorescences 2-3 mm in diam., sessile; pistillate flowers: tepals 5. Achenes nearly ellipsoidal, tuberculate. Fl. Dec-Jul.

Dense forests along streams, streamside rocks; 600-1000 m. S Guangxi [N Vietnam].