Description from Flora of China
Ficus microstoma Wallich ex King; Urostigma pisocarpum (Blume) Miquel.
Trees, 5-15 m tall, epiphytic when young. Bark gray, smooth. Stipules ovate-lanceolate, ca. 0.8 cm, membranous, pubescent. Petiole robust, 1-1.5 cm, glabrous; leaf blade elliptic to obovate-elliptic, 5-8 × 2.5-4 cm, thickly leathery, with cystoliths on both surfaces, base rounded to broadly cuneate, margin entire, apex mucronate; basal lateral veins short, secondary veins 5-8 on each side of midvein, and abaxially prominent, tertiary veins reticulate. Figs axillary on leafy branchlets or on leafless older branchlets, paired, top-shaped-globose, 5-7 mm in diam., apical pore liplike, sessile; involucral bracts ovate, persistent. Male, gall, and female flowers within same fig. Male flowers: few, near apical pore, sessile; calyx lobes 2, broadly ovate; stamen 1; filament short; anther ovoid. Gall and female flowers: calyx lobes 1 or 2; style short but longer in female flowers; stigma cylindric. Achenes narrowly ovoid, smooth. Fl. May-Jul.
Limestone mountains; 500-2800 m. Guangxi, Guizhou, Yunnan [Brunei, Indonesia, Malaysia, Thailand].