The Oak* 



279 



Inner scales of cup inflexed; southern tree. 

 Inner scales of cup not inflexed. 

 Inner bark of tree bright orange; leaves mostly 



hairy, at least on the veins. 

 Inner bark gray to reddish or yellow; leaves green 

 beneath. 

 Leaves dull, not shining, paler beneath; northern 



tree. 

 Leaves shining above. 

 Cup 10 to 15 mm. broad. 



Cup top-shaped; nut ellipsoid to subglobose; 



northern tree. 

 Cup hemispheric; nut oblong; Texan tree. 

 Cup 15 to 25 mm. broad. 

 Cup much wider than high; eastern tree. 

 Cup about as wide as high; western tree. 

 °° Leaves white-tomentulose or gray-tomentulose beneath; 

 eastern trees. 

 Large trees; leaf-lobes mostly long, lanceolate. 

 Leaves rounded or obtuse at base, 3- to 7-lobed. 

 Leaves cuneate, acute or truncate at the base; 5- to 

 13-lobed. 

 Small tree or shrub; leaf -lobes triangular, short. 

 §§ Leaves 3- to s-lobed above the middle or entire, obovate or 

 spatulate in outline. 

 Cup hemispheric; leaves obovate, brown hairy beneath. 

 Cup saucer-shaped; leaves spatulate to obovate, smooth. 

 Cup shallow; nut over 10 mm. long; leaves thick. 

 Cup deep; nut less than 10 mm. long; leaves thin, 

 tt Leaves entire or rarely with a few teeth toward the apex, linear 

 to elliptic or oblanceolate; Willow oaks. 

 Leaves smooth beneath. 

 Cup very flat. 

 Leaves sharp-pointed, linear-oblong to narrowly elliptic. 

 Leaves blunt, oblong to cuneate-oblong. 

 Cup with a narrow base, saucer-shaped; leaves shining 

 •above. 

 Leaves hairy beneath. 

 Leaves brown hairy beneath; cup mostly hemispheric. 

 Leaves gray-hairy beneath; cup saucer-shaped. 

 ** Leaves persistent. 



Leaves densely white downy beneath; southwestern tree. 

 Leaves green beneath, smooth when mature. 

 Nut long, narrowly ovoid; cup deep; California tree. 

 Nut short, ovoid; cup shallow; southeastern tree. 

 b. Fruit maturing the first season; leaves persistent; leaves oval to orbic- 

 ular, convex; California tree. 

 B. Leaves lobed or entire, rarely bristle tipped; styles very short or none; 



shell of nut mostly smooth inside; White oaks, 

 a. Fruit maturing the second season; leaves persistent. 



5. Q. Calesbxi. 



6. Q. vdutina. 



7. Q. borealis. 



8. Q. ellipsoidalis. 



9. Q. texana. 



10. Q. coccinea. 



11. Q. KeUoggii. 



12. Q. triloba: 



13. Q. pagodajolia. 



14. Q. ilicifolia. 



15. Q. marylandica. 



16. Q. nigra. 



17. Q. microcarya. 



18. Q. Phdlos. 



19. Q. hybrida. 



20. Q. laurijolia. 



21. Q. imbricaria. 



22. Q. cinerea. 



23. Q. hypoleuca. 



24. Q. Wislizeni. 



25. Q. tnyrlijolia. 



26. Q. agrijolia. 



