16 JUGLANDACEAE. 



JUGLANS. Walnut. 

 (Family Juglandaceae). 



Usually trees, sometimes of 

 large size: deciduous. Twigs 

 rather stout, more or less fluted: 

 pith moderate, brown, angular, 

 chambered with rather close thin 

 plates. Buds moderate, with sev- 

 eral scales, superposed and often 

 developing into catkin rudiments, 

 the terminal much larger and 

 with more or less lobed scales. 

 Leaf-scars alternate, shield-shaped 

 or 3-lobed, large, raised: bundle- 

 traces in 3 compound groups: 

 stipule-scars lacking. 



Of recent years black walnut 

 has been planted in some quantity 

 for its wood; and the European 

 walnut furnishes one of the im- 

 portant Californian crops, and in 

 more hardy forms it is recom- 

 mended for other regions. Hy- 

 brids are known between the European walnut and the black 

 walnut, and Juglans rupestris has been thought (undoubtedly 

 wrongly) to hybridize with the Californian live-oak. 



1. Terminal bud elongated: leaf-scar downy at top. 2. 

 Terminal bud short: leaf-scar without a downy line. 3. 



2. Leaf-scars not notched at top. (Butternut). (1). J. cinerea. 

 Leaf-scars notched: twig very stout. J. Sieboldiana. 



3. Twigs gray-pubescent: buds canescent: pith diaphragms 



close together (18 to 1 cm.). (Black w.). (2). J. nigra. 



Twigs and lateral buds glabrescent: bark smooth: pith 



diaphragms 8 to 1 cm. (European walnut). J. regia. 



