28o 



The Oaks 



28. 

 29. 



30. 

 31- 



32- 



33- 



34- 



35- 



Nut small, smooth inside, leaves abruptly short -acuminate; south- 

 western tree. 

 Nut large, silky inside; leaves acuminate to obtuse; California trees. 

 Leaves pale and smooth beneath, at least when old; cup thick. 

 Leaves stellate hairy, at least on the veins beneath; cup thin, 

 b. Fruit maturing the first season. 



* Leaves persistent, mostly evergreen. 

 Southeastern trees. 



Leaves not reticulate-veined. 

 Leaves reticulate-veined. 

 Western and southwestern trees. 



Leaves coarsely reticulate-veined and hairy beneath. 



Leaves oblong to oblong-obovate, acute; cup hemispheric. 

 Leaves obovate, mostly blunt; cup saucer-shaped. 

 Leaves not coarsely reticulate-veined beneath, sometimes 

 finely reticulated. 

 Leaves dark green above. 



Leaves spinulose-toothed to entire, cordate or rounded at 



base; Texas to Arizona. 

 Leaves not spinulose, but sinuate-lobed, rarely entire, 

 narrowed at base; Texan tree. 

 Leaves light green or blue-green. 



Cup-scales, at least the lower, corky-thickened on the 

 back. 



Leaves sinuately 5- to 7-lobed; Arizona tree. 

 Leaves entire, wavy or toothed. 



Leaves hairy beneath even when old. 

 Leaves smooth beneath when old. 



Nut 10 to 15 mm. long; Texas to Arizona. 

 Nut 18 to 25 mm. long; southern California. 

 Cup-scales thin, scarcely thickened on the back; Arizona 

 tree. 

 ** Leaves deciduous. 



Leaves blue-green; California tree. 

 Leaves yellow-green to dark green, 

 t Leaves entire, wavy or lobed only near the apex. 

 ' Cup saucer-shaped. 



Leaves hairy beneath; cup thin. 

 Leaves smooth; cup thick. 

 Cup hemispheric. 

 Leaves coarsely lobed toward the apex, smooth when 



mature. 

 Leaves irregularly lobed or angulate, jjersistently pubes- 

 cent beneath, 

 tt Leaves coarsely toothed or lobed nearly all around. 



Leaves crenate or shallowly lobed; Chestnut oaks; eastern trees. 

 Acorns sessile or nearly so. 



Low tree or usually a shrub; leaves obovate. 46. 



Tall trees. 



Leaves oblong to lanceolate or some of them 

 obovate; bark close. 47- 



27. Q. Wilcoxii. 



Q. chrysolepis. 

 Q. tomenteUa. 



Q. virginiana. 

 Q. geminata. 



Q. arizonica. 

 Q. reticulata. 



Q. Emoryi. 

 Q. breviloba. 



42. 



43- 



44. 



45- 



Q. Durandii. 

 Q. Laceyi. 



Q. austrina. 

 Q. Chapmani. 



Q. prinoides. 

 Q. Muhlenbergii. 



