224 MISC. PUBLICATION 42 3, U. S. DEPT. OF AGRICULTURE 



1. Shell of the fruit not tomentose within; abortive ovules basal; cup scales much 

 thickened basally, narrowed at apex; stigmas short and broad; leaves, if 

 toothed, not aristate; bark commonly gray and scaly or flaking: Sub- 

 genus Lepidobalanus , White oaks (4). 

 4. Leaves deciduous in autumn, deeply incised or crenate, the lobes round, not 

 mucronate (5). 

 5. Leaves shallowly crenate-lobed, about 3 to 4.5 cm. long. 



9. Q. SUBOBTUSIFOLIA. 



5. Leaves deeply incised with narrow lobes, 8 to 10 cm. (rarely only 3 to 5 



cm.) long 10. Q. gambelii. 



4. Leaves persistent until spring, entire, mucronate-serrate, or acutely shallow- 

 lobed (6). 



6. Veins slightly impressed above, markedly prominent beneath, the blades 



usually mucronate, or toothed toward the apex (7). 

 7. Leaves concave beneath, obovate to suborbicular, the base strongly 

 cordate; fruit long-stalked 1. Q. diversicolor. 



7. Leaves flat, narrowly obovate to oblanceolate, the base usually cordate, 



occasionally rounded to subcuneate; fruit subsessile. 



3. Q. ARIZONICA. 



6. Veins not impressed, usually somewhat prominent above, not markedly 

 prominent beneath, the margins entire or toothed (8) . 



8. Leaves oblong, rounded at both ends or cordate at base, glabrous, very 



glaucous, the margins entire 2. Q. oblongifolia. 



■ 8. Leaves not oblong or rounded at both ends or, if so, then not glabrous or 

 glaucous, the margins entire or toothed (9). 



9. Blades medium sized, 2 to 4 cm. wide, 3 to 6 cm. long, more or less 



undulate-crisped, roughly short-pubescent or scabrous to the touch 

 (10). 



10. Leaves ovate, mucronately shallow-lobed, somewhat crisped, mod- 



erately rough-pubescent 7. Q. undulata. 



10. Leaves oblong, pungently lobed, strongly crisped with the lobes 



appearing twisted, harsh and scabrous like sandpaper. 



8. Q. PUNGENS. 

 9. Blades usually small, 0.5 to 2 cm. wide, 1 to 5 cm. long, entire, or 

 if toothed, then flat, glabrate or soft-hairy (11). 



11. Leaves narrowly elliptic to lanceolate, usually very small, acute, 



entire or rarely with a few short teeth, very sparsely pubescent 

 beneath with soft white hairs, shiny above; bark roughly scaly or 



flaky on branches 5 years old 5. Q. toumeyi. 



11. Leaves broadly elliptic, broadly lanceolate, or ovate (12). 



12. Leaf blades entire or with a few mucronate teeth, relatively large, 

 elliptic to broadly lanceolate or ovate, usually obtuse but some- 

 times acute and mucronate at apex, gray green or blue green, the 

 upper surface shining and sparsely stellate-pubescent, the lower 

 surface perceptibly roughened with stellate hairs. 



4. Q. GRISEA. 



12. Leaf blades almost aristately many-toothed, small, broadly 



elliptic to ovate, glaucous, the upper surface dull, nearly 



glabrous, the lower surface with white or yellow resinous 



pubescence 6. Q. turbinella 



1. Quercus diversicolor Trel., Natl. Acad. Sci. Mem. 20: 73. 1924. 



Quercus reticulata of authors. Not Humb. and Bonpl. 



Southern Coconino County to Cochise and Pima Counties, 4,000 

 to 6,500 feet, mostly in canyons, nowhere very abundant. Western 

 Texas to central and southern Arizona and northern Mexico. 



Netleaf oak. Not very closely related to any other species in the 

 United States, its nearest relatives being the Mexican Q. reticulata 

 Humb. et Bonpl., to which the Arizona material was formerly 

 referred, and Q. durangensis Trel. It occurs as a low or tall tree or a 

 shrub, from 2 to 12 m. (6.5 to 40 feet) high. The typically broadly 

 obovate leaves, with several subaristate teeth about the round apex 

 and strongly reticulate-veined beneath, make this species readily 



