206 



EUPHORBIACE^;. 



[CLASS 



said to be one of the most productive yielded by any 

 food-plant. 



Several species afford important drugs, as Castor Oil, 

 obtained from the seeds of Ricinus, and Croton Oil, from 

 the seeds of Croton Tiglium. African Teak (Oldfieldia) 

 and the Box (Buxiis) yield valuable wood; the latter 

 furnishing the blocks used by wood-engravers, for whose 

 purposes its close texture and hardness eminently fit it. 

 It is native in South and South-Eastern Europe, and 

 grows in some wild situations in England, but it may have 

 been introduced long ago to the latter. 



56. Natural Order Urticaceae. The Nettle Family. 



DISTRIBUTION. Cosmopolitan, but most numerous 

 between the Tropics. British genera 3, species 5. 



Stinging herbs. Flowers unisexual. Ovary i-celled, with I 

 erect ovule. 



Type Small Nettle (Urtica urens). 



An annual herb, with opposite simple leaves, stinging 

 hairs, and axillary clusters or spikes of small monoecious 

 flowers. 



OBSERVE the stamens opposite to the leaves of the 

 perianth, and their elastic filaments, flying back when 

 released by vhe expansion of the flower. 



