Stout, monoecious herb, usually with few short-stalked stinging hairs, otherwise sparsely to densely hairy; branches decumbent and rooting, then erect. Lvs broadly ovate, acute, cordate to truncate at base, coarsely serrate, 10-20 cm long. Stipules 2 per node and 2-fid, or 4 per node and entire. Most racemes unisexual; ♀ racemes above ♂ on stem.