JUGLANDACE^. SILVA OF NORTH AMERICA. 



117 



The species of Juglans can be easily raised from seeds^ which should not be allowed to dry before 

 they are planted^ as they soon become rancid and lose their power of germination.^ The varieties can 

 be propagated by grafting. 



The generic name^ the classical name of the Walnut-tree^ from Jupiter and glanSy was adopted by 

 Linnaeus, who discarded the older Nux of Tournefort.^ 



also on Hicoria and are not the cause of serious disease. Micro- ever, this fungus does comparatively little damage. A spot disease 

 stroma JuglandiSy Saccardo, one of the most generally distributed is produced on the leaves of Juglans nigra by Cercospora JuglandiSy 



Walnuts 



KeUerman & Swingle. 



whitish layer on the under surface of the leaves, causing them to ^ Cobbett, Woodlands ^ Bi4:. — Fuller 



shrivel un. In 



346 



CONSPECTUS OF THE NORTH AMERICAN SPECIES. 



Fruit racemose ; nut prominently 4-ribbed at the sutures, 2-celled at the base ; heartwood light brown. 



Leaflets 11 to 17, oblong-lanceolate 1. J. cinerea. 



Fruit usually solitary or in pairs ; nut without sutural ribs, 4-celled at the base ; heartwood dark brown. 



Leaflets 15 to 23, ovate-lanceolate ; nut deeply and irregularly ridged 2. J. istigra. 



Leaflets 9 to 23, lanceolate to ovate-lanceolate ; nut deeply sulcate 3. J. rupestris. 



Leaflets 11 to 17, ovate-lanceolate ; nut obscurely sulcate 4. J. Californica. 



