JUGLANDACEAE 



The Walnuts 



Characteristics of the Genus Juglans L. 



HABIT. Small to large handsome trees; crowns broad and 

 open; stout, ascending branches. 



LEAVES. Alternate; pinnately compound; deciduous; native 

 species with 9-23 sessile, oblong-lanceolate, finely serrate, acute 

 to acuminate leaflets. 



FLOWERS. Monoecious; apetalous; appearing with or after 

 the leaves; staminate in preforined aments, with 8-40 stamens; 

 pistillate in spikes of 2-8 flowers, each with a 2-celled ovary 

 and 2 divergent, plumose stigmas. 



FRUIT. A drupe-like nut encased in a semifleshy, indehis- 

 cent husk; maturing in one year; nut thick-shelled, containing 

 solitary, 2-4 lobed, sweet, oily, edible seed. 



TWIGS. Stout; round; with characteristic chambered pith. 

 Winter buds: terminal present, few-scaled. Leaf scars: con- 

 spicuous, with three U-shaped bundle scars. 



WOOD. Dark-colored; durable; diffuse-porous; valuable. 



SILVICAL CHARACTERS. Intolerant; deep taproot; nuts 

 disseminated largely by rodents or streams. 



GENERAL. Of the six native species only the two eastern 

 are of commercial importance and treated separately. The four 

 southwestern species are distinguished in the key. They are: 



1 . California Walnut, Juglans calif ornica S. Wats. 



2. Hinds Walnut, Juglans hindsii Jeps. 



3. Arizona Walnut, Juglans major (Terr.) Heller. 



4. Little Walnut, Juglans microcarpa Berl. {J. rupestris Engelm. ) 



The Persian or English walnut, Juglans regia L., is widely 

 planted in warmer parts of the country and is included in the 

 key. The variety with thin-shelled nuts is commonly marketed 

 and the wood is widely used under the name of Circassian walnut. 



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