BETULACEAE. 



61 



7. Twigs glabrate. (Shagbark hickory). C. ovata. 



Twigs persistently hairy. C. ovata hirsuta. 



Family BETULACEAE. Birch Family. 



A small family chiefly of cold regions, furnishing some im- 

 portant lumber and the hazel nuts and filberts of commerce ; 

 much planted for single tree effect. 



CORYLUS. Hazel. Filbert. 



Deciduous shrubs with light brown wood with minute ducts 

 in radial or flame-like patterns and very fine medullary rays ; 

 moderately slender rounded often bristly twigs ; roundish homo- 

 geneous pale pith ; alternate low crescent-shaped leaf-scars with 

 3 often compound bundle-traces ; narrow stipule-scars ; ovoid buds 

 with half-a-dozen exposed scales ; rather large broad but pin- 

 nately veined stalked simple leaves ; inconspicuous monoecious 

 apetalous flowers in catkins ; and light brown hard-shelled rather 

 small nuts in green or membranaceous husks. 



1. Husk of 2 nearly or quite separate bracts. 2. 

 Husk tubular. 8. 



2. Husk bur-like. 

 Husk unarmed. 3. 



3. Husk parted into linear divisions. 

 Husks with broader divisions. 4. 



4. Husk open, hardly longer than the short nut. 5. 



Husk closely applied to and surpassing the nut. C. americana. 



C. ferox. 

 C. colurna. 



5. Leaves laciniate. 



Leaves not deeply parted. 6. 



6. Rather upright. 7. 

 Branches drooping. 



7. Leaves green. (European hazel) 

 Leaves yellow. 



Leaves purple. 



8. Husk merely pubescent : nut elongated. 

 Husk bristly. 



9. Leaves green. (Filbert). 

 Leaves purple. 



C. Avellana laciniata. 



C. Avellana penduh, 

 C. Avellana. 

 C. Avellana aurea. 

 C. Avellana atropurpurea. 



9- 



C. rostrata. 



C. maxima. 

 C. maxima purpurea. 



