Nettles For Food and Medicine :: Botany

Nettles For Food and Medicine Despite its nondescript appearance, the stinging nettle (Urtica dioica) has a knack for grabbing the attention of anyone passing by. Unfortunately, most people never notice nettles until they are viciously attacked with sharp, hot, itching stings. Consequently, most people familiar with nettles regard them as pesky and undesirable weeds. Few people today realize that nettles may actually be counted among nature's most useful plants. As is frequently the case with common names, the term nettle is often used for plants that aren't nettles at all. In the Midwest, the plant known as Red Dead-Nettle is actually a member of the Mint Family and the Horse Nettle (which is poisonous) is actually a Nightshade (Seymour, 1997). The true nettles belong to the Urticaceae, also known as the Nettle Family. The Nettle Family is found worldwide and consists of about 45 genera and 700-1000 species. Most of the species are tropical and herbaceous (Walters and Keil, 1996). Urtica dioica, the plant most often called by the name Stinging Nettle, is a dioecious perennial plant that stands about one meter tall. It has simple, opposite, toothed leaves (5-10cm long) with persistent stipules and, most importantly, stinging trichomes. The radially symmetrical flowers are arranged in axillary panicles, completely lack petals, and have 4 sepals and 4 stamens. The fruits are small, oval achenes (1-2mm long). In addition to growing from seed, the plants are able to spread rhizomatously (Radford, Ahles and Bell, 1968). The Stinging Nettle is actually not nearly as common in the U.S. as the closely related Wood Nettle (Laportea canadensis). The Wood Nettle is often mistaken for the Stinging Nettle by most people because the Wood Nettle also has stinging hairs. Laportea canadensis is not as tall as Urtica dioica, has larger leaves (up to 20cm) and minute stipules. The staminate flowers have 5 sepals and 5 stamens and are found in axillary panicles. The pistillate flowers have only 4 sepals and are found in either terminal or axillary panicles. The achene is crescent-shaped (Radford, Ahles and Bell, 1968). The wood nettle grows well in rich forests and may be particularly abundant along hiking trails near streams. Hikers are frequently dismayed to discover that when such trails aren't carefully maintained, nettles quickly begin to arch dangerously over the paths. There are several other species from the Nettle Family in the United States, but only 4 of the genera represented, Urtica, Hesperocnide, Laportea, and Urera, have the characteristic stinging trichomes.