HICKORIES 225 



The common hop (Humulus lupulus) is well known. It 

 is used in making yeast, beer and medicine. 



Fig and Rubber. The genus Ficus includes the common 

 fig (Ficus carica) (Fig. 147), the India rubber tree (F. elas- 

 iica) and the banyan tree (F. bengalensis) . 



The hemp (Cannabis sativa) also belongs to this family. 



Propagation. The mulberry is usually grown from root 

 cuttings, or from layerings, or by budding. New varieties are 

 obtained from seeds. The elms are usually grown from seeds 

 which mature very early in the spring and are sown at once, 

 but may also be grown by layering or by grafting. Hops may 

 be grown from seeds, from divisions or from hard wood cut- 

 tings. Hemp is grown from seed and is one of the very im- 

 portant fibre plants. 



WALNUT FAMILY ( JUGLANDACE^E) 



This very important family contains two valuable groups of 

 trees, the walnut and the hickory. The flowers are monoecious. 

 The staminate flowers are usually borne in catkins and each 

 consists of a six-lobed (occasionally two- or three-lobed) peri- 

 anth and from six to forty stamens. The pistillate flowers are 

 terminal and may be solitary, few or clustered ; the calyx tube 

 is four-toothed and styles two in number. The fruit is a dru- 

 paceous nut. 



Walnuts. The American black walnut (Juglans nigra) is 

 well known both for the nuts and for the high quality of the 

 wood. The American butter-nut (J. cinerea) produces an ex- 

 cellent nut, but the wood is not so valuable as that of the black 

 walnut. The so-called English walnut (/. regia), which is now 

 extensively cultivated in many parts of the world, is of Asiatic 

 origin. It is of great value both for nuts and lumber. 



Hickories. The various species of hickory (Hicoria ovata, 

 15 



