402 



JUGLANDALES URTICALES 



which serves to catch the spores when no winds are stirring 

 and thus prevent their falling to the ground. 



140. Other Tree Orders Suggestive of the Fagales. Closely 

 allied to the Fagales is the order of the walnuts, Juglandales, 

 including the black walnut and butternut (Juglans) and the hick- 

 ories (Hicoria, Fig. 301). These trees are of very common 



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 ex- 

 posing the hard inner part, the shell of the nut. 



occurrence in the northern United States and characterized by 

 their aromatic oils and large compound leaves. The flowers are 

 very similar in structure and arrangement to those of the beech 

 order, but at maturity the outer part of the wall of the ovary 

 becomes transformed into a fleshy rind and the inner portion 

 forms a hard shell. In the walnut this pulpy, aromatic rind 



