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. Alnus. 329. 
1. Alnus incana Willd. 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-rin. 
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. 
