206 FOREST TREES OF THE PACIFIC SLOPE. 



sperms. Examples of broadleaf trees with resin in their wood are the cherries, 

 plums, acacias, mesquite, red gum (Liquidambar) , etc., in which the character 

 of the resin is distinctly mucilaginous. 



Family JUGLANDACE^. 



The distinctive characters of Juglandaceae are that male and female flowers 

 are each borne on different parts of the same tree and that the fruit is a nut 

 (1) with a firm pulpy covering which does not break open of its own accord 

 (walnuts), or (2) with a firm woody covering which separates at maturity 

 into 4 nearly distinct or partly connected, rind-like divisions (hickories). 

 The single hard-shelled nut is usually soon liberated from the latter type 

 of covering, but the undivided pulpy covering of the former type dries and 

 adheres to its nut until rotted away by contact with the ground. The leaves 

 of the trees representing this family occur singly and more or less distant from 

 each other — never growing in pairs, one leaf exactly opposite its fellow, as in 

 trees of some other families. A very important group of timber trees. 



JUGLANS. WALNUTS. 



The walnuts are a small group of trees very sparingly represented in the 

 Pacific region. They are important forest trees, some of them producing very 

 handsome and exceedingly valuable lumber. Pungent aromatic odor is charac- 

 teristic of leaves and other green parts when bruised, while the heartwood is a 

 rich dark brown. Distinctive characters of the branches are the leaf-scars with 

 3 groups of minute dots, and the partition-like structure of the pith (best seen 

 by slicing a twig longitudinally). The leaves, called compound because they dif- 

 fer from the ordinary simple leaf (an apple leaf) in being made up of a single 

 central stem from which grow from 5 to 11 pairs of pointed leaflets (each 

 appearing like an ordinary leaf). By the suppression of one leaflet of the 

 terminal pair, the number of leaflets may be odd. The flowers appear after the 

 leaves. Male flowers (pollen bearing) are long, flexible, cord-like, pendent 

 bodies, borne singly or in pairs from buds of branches grown the previous sea- 

 son ; female flowers, which develop into fruit, are bud-like bodies borne in small 

 clusters at the ends of the new green shoots of the season, usually on the same 

 branch as contains the male flowers. The fruit, a spherical nut (in Pacific 

 representatives), is matured in the autumn of the first season. Its firm, pulpy 

 husk breaks up after maturity, but with no regular divisions. The heavy 

 nuts are dependent for their distribution upon the agency of rodents, which 

 bury many of them for their winter food, and upon floods, which often carry 

 them long distances. 



One only of the four species indigenous to the United States occurs in the 

 Pacific region and it is confined to western California. Other representatives 

 of the genus are world-wide in their distribution. 



The walnuts are of ancient origin. Remains of numerous ancient species, once 

 common in Europe but now extinct, have been found in the Cretaceous and Ter- 

 tiary formations, while in the northern Pacific coast region signs of ancient 

 walnuts have been obtained from the Eocene formation, as well as from gold- 

 bearing gravel beds of the California Sierras. No living representatives are 

 found in these regions now. 



California Walnut. 

 Jufflans calif arnica Watson. 

 DISTINGUISHING CHARACTERISTICS. 



Though it ranges in size from a shrub to a tree 50 feet high and from 8 to 

 15 inches in diameter, California walnut is usually a low, wide-crowned tree 



