140 



Fam. 6. Urticaceae. 



Herbs, rarely half-shrubs, some armed with stinging 

 hairs which inject an acid fluid when penetrating the 

 skin. Flowers unisexual, monoecious or dioecious; peri- 

 anth 3 — 5 -parted or tubular and toothed, x flowers • 

 stamens as many as ealyx lobes, mostly 3- 5, or 1 ; 

 filaments inflexed in the bud, elastically stretching when 

 ripe, thus scattering the pollen. ? flowers with or without 

 a perianth; ovary i-celled, with 1 stigma and 1 basal, 

 erect ovule. Fruit an achene. (Plate 23, page 134.) 



Some species yield a valuable fibre, viz. U?~tica ca?i?ia- 

 bi?ia^ U?~era tenax and BoeJi7neria ?iivea, the ramie-plant. 



KEY TO THE GENERA. 



A. $ flowers with 3 — 5 stamens. 



a. Leaves with stinging hairs (S. A.). 



I. Leaves opposite ; stigma penicillate ; achene equal-sided. 

 About 30 species, 2 native and 2 introduced. 



1. Urtica Tourn. 



II. Leaves alternate. 



1. Stigma capitate. 



(Trop.) 2 species in Na. 2. Urera Gaud. 



2. Stigma linear. 



4 S. A. species (E., N.). (Plate 23.) 3. Fleurya Gaud. 



b. Leaves unarmed. $ flowers with a tubular, 3 — 4-toothed perianth 



enclosing the ovary. 



2 S. A. species (N.). 4. Pouz61zia Gaud. 



B. f flowers with 1 stamen. 



a. $ and $ flowers together in involucred glomerules. 



I. Involucral bracts free or nearly free ; perianth of £ flower tubular, 

 of ¥ wanting. Herbs with rigid hairs. 



1 S. A. species. F. Candida. No. 5. Forsk6lea* L. 



II. Involucral bracts forming a bell-shaped cup toothed at the 

 margin. Smooth herbs. 



1 S. A. species. D. ambigua. 6. Droguetia Gaud. 



b. t and ¥ flowers together in nude glomerules; perianth of £ flower 



obliquely funnel-shaped, the limb hood-like, acuminate. 



3 S. A. species. {Didymodoxa E. Mey.) 



7. Australina Gaud. 



* Named after Peter Forskol, a pupil of Linnaeus and later professor of botany 

 at Copenhagen. He died during a journey of exploration in Arabia, 1763. 



