Mulberry-weed

Urtica villosa Thunberg, Fl. Jap., 70. 1784

Herbs , to ca. 8 dm. Stems erect, branched, pubescent with hooked trichomes. Leaves: stipules linear to linear-lanceolate, 1.8-2.5 mm; petiole 1-6 cm, often ± as long as leaf blade. Leaf blade to 2.5-10 × 1-7 cm, papery, base cordate to truncate, margins crenate-dentate, apex acute to acuminate; surfaces abaxially and adaxially appressed-hirsute. Inflorescences cymes, dense, 4-8 mm wide, subtended by narrow bract; peduncle 1-2 cm. Flowers light green, staminate and pistillate in same cyme. Staminate flowers: calyx campanulate; stamens exserted. Pistillate flowers: calyx boat-shaped; ovary globose, puberulent, somewhat depressed in axis; style reddish purple, filiform. Achenes white, oval, 3-angled, ca. 1 mm, minutely muricate, with 2 triangular, membranous appendages. Seeds explosively expelled.

Flowering summer-fall. Disturbed sites; 0-300 m; introduced; Ala., Ark., Fla., Ga., Ky., La., Md., Miss., Mo., N.C., Ohio, Okla., S.C., Tenn., Tex., Va., W.Va.; West Indies (Bahamas); native to Asia.

Fatoua villosa was first reported for North America from Louisiana by J. W. Thieret (1964). It has become widespread in the eastern and lower midwestern states where it often occurs as a weed in greenhouses and disturbed sites. Apparently it spreads from the distribution of horticultural materials.