DEVELOPMENT OF PLANTS 



435 



common with the beech order and contains several of our com- 

 mon trees as the elm {Ulmus, Fig. 302), hackberry (Celtis), mul- 

 berry (Morus), osage orange (Toxylon), numerous tropical 

 forms, as the India rubber trees, banyan tree, etc., as well as a 

 variety of valuable herbaceous plants, as the hop and hemp. 

 These plants very generally contain a milky juice, latex, which 





FiG. 301. Flower and fruit of the Juglandales: A, inflorescence of but- 

 ternut — s, staminate ament; p, pistillate inflorescence. The butternut and 

 black walnut (^Juglans) may be recognized by the chambered pith, as shown 

 at bottom of twig. B, section of a pistillate flower — pr, perianth adnate to 

 the two carpels composing the pistil; s, stigma. C, fruit of hickory, the 

 outer part of ovary wall splitting into four valves and exposing the hard inner 

 part, the shell of the nut. 



in the case of Ficus and Castilloa, two of the India rubber trees, 

 furnishes the raw material of India rubber and in the cow tree 

 of South America yields a saccharine, nutritious milky juice. 

 Tough stereome fibers are characteristic features in many of 

 these plants and furnish the hemp derived from the Cannabis, 

 and in Japan paper is manufactured from the fibers of the paper 



