Description from Flora of China
Sphaerotylos C. J. Chen.
Shrubs or small trees, evergreen, without stinging hairs. Leaves alternate, spiral; stipules deciduous, intrapetiolar, 2-cleft; leaf blade 3-veined, margin serrulate; cystoliths punctiform. Inflorescences in axillary pairs, cymose panicles, lateral branches usually few and short, unisexual (plants dioecious); glomerules contiguous, forming dense spikes. Male flowers: perianth lobes 5, connate at base, imbricate; stamens 5; filaments inflexed in bud; rudimentary ovary present. Female flowers: perianth lobes 4 or 5, connate at base, submembranous at anthesis, enlarged and fleshy in fruit, unequal, ventral 1(or 2) lobes smaller, ovate to lanceolate, connate with others at base, dorsal 3(or 4) lobes larger, connate to apex, swelling to ventricose tube, staminodes absent. Ovary without style; stigma sessile, ringlike, with villous hairs; ovule orthotropous. Achene somewhat drupaceous, ovoid to obliquely obovoid, covered but not enclosed by fleshy perianth. Seeds with little endosperm; cotyledons ovate.
The discovery of the ringlike stigma in the family Urticaceae (C. J. Chen, Acta Phytotax. Sin. 28: 469. 1990) corrects the mistaken description of a penicillate stigma in the protologue of this genus. This interesting character seems useful in explaining the evolution of the family.
One species: tropical Asia from E Himalayas through Thailand to Indonesia.
(Authors: Chen Jiarui (陈家瑞 Chen Chia-jui); Ib Friis, C. Melanie Wilmot-Dear)