FAMILIES OF FLOWERING PLANTS. 



83 



dry and winged (called a samara) and in other genera, either a drape 

 (stone-fruit) or nut. 



Family Moraceae. iMulberry Family. Contains ai)out 55 genera 

 and Mearly 1000 species, natives largely of tropical regions. 600 

 species belong to the single genus ivV//.s', the tig, which is of immense 

 economic importance, as it is the chief source of caoutchouc and 



furnishes us also with deli- 

 cious fruits. Strictly speak- 

 ing, the part which is eaten 

 is not the fruit, l)ut the pidpy 

 receptacle, in which are em- 

 bedded,* the numerous small 

 dry achenes commonly known 

 as seeds. A similar condition 

 exists in J/oz-i/s^ the mul- 

 berry; the claims of this 

 tree to economic considera- 

 tion lie chiefl}^ in the fact 

 that it is the best food for 

 silkworms. The Moraceae 

 are distino;uished from the 

 preceding family by the 

 structure of their fruit, and 

 by the presence of a milky 

 sap. Among the genera of 

 interest may be mentioned 

 Artocdi'jnis^ the breadfruit, 

 which is an important item 

 in the dietary of the natives 

 where it grows; Brosimum, 

 the "cow-tree' ' of Venezuela, 

 the sap of which furnishes a 

 pleasant drink; Ilunnilnx, the common hop; BroiiHsonetia, the paper 

 mulberry, an ornamental tree which has become naturalized in the 

 eastern United States; and Cannah!s, the hemp. 



Family Urticaceae. Nettle Family. Contains al)out 40 genera 

 and nearly 500 species, very widely distributed. The majority are 

 herbs, many of them provided with painfully stinging hairs. The sap 

 is watery, and not of milky consistency, while the fruit is an achene. 



Fig. 68.— The Hrmp Plant. Can.nahi.t sutira. After 

 Dodge, Rept. No. 9, U. S. Dept. of Agric. 



