BETULACE^ 



29 



FiQ. 24. — Populus deltoides. 



1. CORYIiUS. Hazelnut. 



Sterile flowers consisting of 8 stamens and a pair of scaly bracts, 

 in catkins in the axils of the branches of the preceding year; fertile 

 flowers clustered in a scaly bud at the ends of the shoots, easily 

 recognized by the long, slender red stigmas appearing before the 

 leaves in early spring; fruit a nut with much thickened coty- 

 ledons and enclosed in a leaf-like involucre. Shrubs with thin 

 double-toothed leaves folded lengthwise in the bud. 



1. C. americana, Walt. Hazelnut. 



Involucre of 2-toothed and somewhat distinct bracts opening down to 

 and disclosing the globular nut. Thickets, Man. and Sask. 



2. C. rostiata, Ait. Beaked Hazelnut. 



Bracts of the involucre united and prolonged above the nut into a tubular 

 beak densely covered with minute bristles; nut ovoid. Thickets, Man.- 

 Alta. 



2. OSTRYA. Ironwood. 



Sterile flowers in slender drooping catkins with several stamens in 

 the axil of each bract; fertile flowers in shorter catkins, two in 



