“ It contains 41 genera, with about 500 species, mainly tropical, though several species such as the common stinging nettle (Urtica dioica) are widely distributed and occur in large numbers in temperate climates. Two genera are represented in the British Isles, Urtica (see Nettle) and Parietaria (pellitory, q.v.) .
The plants are generally herbs or somewhat shrubby, rarely, as in some tropical genera, forming a bush or tree. The simple, often serrated, leaves have sometimes an alternate sometimes an opposite arrangement and are usually stipulate—exstipulate in Parietaria. ”

“ The position of the stipules varies in different genera; thus in Urtica they are lateral and distinct from the leaf-stalk, in other cases they are attached on the base of the leaf-stalk or stand in the leaf-axil when they are more or less united. Stinging hairs often occur on the stem and leaves (fig. 1) . ”

“ A stamen is opposite each sepal, and in the centre of the flower is the rudiment of a pistil.
From Vines’s Students’ Text-Book of Botany, by permission of Swan Sonnenschein & Co.
Fig. 3.—A staminal (♂) , B carpellary (♁) flower of the Nettle. p, perianth; a, Stamen; n′, rudimentary ovary of the ♁ flower; ap, outer, ip, inner, whorl of the perianth; n, stigma of the ♂ flower (enlarged) . stem are generally long and firmly attached end to end, and hence of great value for textile use. Thus in ramie (q.v., Boehmeria nivea) a single fibre may reach nearly 9 in. ”