SPERMATOPHYTA— URTICACEAE 



409 



Urticaceae. Nettle Family 



Herbs, trees, or shrubs with stipules; flowers monoecious or dioecious, 

 rarely perfect; calyx from the 1-2-celled ovary which forms a 1 -seeded 

 fruit ; stamens as many as the lobes of the calyx or sometimes fewer ; opposite, 

 ex-albuminous or albuminous ; when albuminous the radical points upward ; 

 cotyledons broad. A small family of 500 species some of which, like Boehmeria, 

 produce valuable fibers. The leaves of Pilea puinila are demulcent and are 

 said to be valuable in Rlius poisoning. 



Fig. 190. Slippery Elm (Ulinus fulva). 1. Flowering branch. 

 3. Fruiting branch. 3. Winter branch with buds. 4. Same show- 

 ing flower buds beginning to enlarge. 5. Summer branch. 6. Flower 

 enlarged. 7. Longitudinal section of flower, enlarged. 8. Longitud- 

 inal section of pistil, enlarged. 9. Stamen, enlarged. 10. Cross 

 section of ovary, enlarged. 11. Longitudinal section of fruit. 12. 

 Seed, enlarged. 13. Longitudinal section of seed, enlarged. 14. 

 Embryo, enlarged. 1, 2, 3, 4, 5, 11, one-half natural size. (After 

 M. M. Cheney, in Green's Forestry in Minnesota.) 



