FAGACEAE 157 



2. Ostrya. 327. 



1. Ostrya virginiana (Mill.) Willd. Ironwood, Hop Hornbeam. 



Along streams in the eastern and northern parts of the state. Belle- 

 vue; Long Pine; Nebraska City; Ponca; South Bend; Weeping 

 Water. 



3. Corylus. 327. 



1. Corylus americana Walt. Hazel-nut. 



Along streams in the eastern part of the state. Fremont; Nebraska 

 City; Omaha; Peru; Weeping Water; Wymore. 



4. Betula. 327. 



Bark chalky white, leaves dentate or serrulate. 1. B. papyrifera. 



Bark greenish-brown or brown, leaves coarsely serrate. 



2. B. fontinalis. 



1. Betula papyrifera Marsh. Paper or Canoe Birch. 

 In the northwestern part of the state, not common. Brown County; 

 Ft. Niobrara; Merriman; Valentine. 



2. Betula fontinalis Sarg. Black Birch. 

 Betula occidentalis Hook . 



In the northwestern part of the state. Harrison; Hat Creek Basin. 



5. AInus. 329. 



1. AInus incana Wllld. Alder. 



Along the Missouri in eastern Nebraska. 



6. FAGACEAE. 



Quercus. 332. 



Leaves merely toothed, not lobed. 



Trees; leaves lanceolate. 1. Q. acuminata.' 



Shrubs; leaves ovate or obovate. 2. Q. prinoides. 



Leaves deeply lobed. 



Lobes not bristle-tipped; acorns annual, i. e. maturing in one season. 



Terminal lobes of the leaf not much larger than the lower; acorn 



much longer than the shallow cup. 3. Q. alba. 



Terminal lobes of the leaf much larger than the lower; acorn 



scarcely longer than the cup. 4. Q. macrocarpa. 



Lobes bristle tipped; acorns biennial, i. e. requiring two seasons 



to mature. 



Leaves pinnately lobed. 



Sinuses extending about half-way to the mid-rib; the lobes 

 tapering to the apex. 5. Q. rubra. 



Sinuses extending more than half-way to the mid-rlp. 



Leaves glabrous, very deeply lobed. 6. Q. coccinea. 



Leaves pubescent when young, less deeply lobed. 



7. Q. velutina. 

 Leaves obovate, 3-5 lobed towards the apex. 8. Q. marylandica. 



