SECT. II 



PHANEROGAM I A 



557 



their nests, where they are kneaded up into a mass upon which the fungal cultures 

 are made ; this fungus is the sole food of these ants. While the facts observed by 

 Belt and Muller are well established, their connection with the protection 

 afforded by the ants in the stem has become doubtful. A^arious observers have 

 shown that Cecropia can exist quite ■well without the defending ants, that the 

 leaf-cutting ants are less injurious than other animals and insects, and lastly, that 

 those more injurious forms are left unmolested by the defensive ants. The forma- 

 tion of Muller's bodies must thus have some other explanation. Similar structures 

 occur in other plants and remind one of the exti'a-floral nectaries. 

 Official. — The fruits of Ficus carica. 



Fio. 533. — Hwnuliis Inpulus. 1, Male inflorescence. S, Female inflorescence. 3, Two female 

 flowers in the axil of a bract. /,, Cone-like inflorescences in fruit. (A nat. size.) 



Family 3. Cannabinaceae. — Annual or perennial herbs without latex, with 

 palraately veined leaves and free, persistent stipules. Dioecious. Male flowers 

 pentamerous ; stamens straight in the bud. The male inflorescences are dichasia, 

 the central branch capable of further growth. The female flowers have a slightly 

 developed, entire perianth. Ovary bicarpellary, with two large feathery stigmas ; 

 unilocular, with a pendulous, anatropous ovule. Anemophilous. Fruit, nut-like. 

 Embryo curved. 



Genera. — Hwmulus lupulus, the Hop, is a native of central Europe ; it has a 

 perennial rhizome, which annually produces a cro[) of twining shoots (Fig. 533). 

 The stem and opposite leaves bear coarse hairs, and the former bears hooked 

 prickles which prevent it slipping down the support. The branches of the female 

 inflorescence are catkin -like, the scales being formed of the pairs of stipules 

 belonging to bracts, the laminae of which are suppressed. The axillary shoot of 



