Aquatic and Wetland Vascular Plants of the Northern Great Plains
Urticaceae - The Nettle Family
Monoecious or dioecious, annual or perennial herbs with watery juice, sometimes
beset with stinging hairs, the leaves opposite (in those included here),
simple, petiolate, usually stipulate. Flowers small, greenish and inconspicuous,
borne in simple or branched axillary clusters, usually imperfect; perianth
consisting of a 3- to 4-parted or toothed calyx, that of the male flowers usually
more deeply parted; stamens equal in number to the calyx lobes and opposite
them, a vestigial pistil sometimes present; female flowers containing
a unicarpellary pistil and sometimes with scalelike rudiments of stamens, style
1, ovary superior, 1-celled, ovule 1. Fruit an achene, often enclosed
by an accrescent calyx.