STANDLEY — TREES AND SHRUBS OF MEXICO. 175 



Leaves elongate- obovate, subglabrescent 34. Q. bonplandiana. 



Leaves round-obovate or subelliptic. 



Leaves creuate 35. Q. rugosa. 



Leaves repandly mucronate, whitened beneath. 



36. Q. reticulata. 

 AAA. Leaves, or most of them, entire ; fruit nearly sessile. 



E. Leaves tomentose beneath and rugose above, or else blue-green or very 

 small. 



Leaves relatively large (fully 2 cm. wide and 4 cm. long), very rugose 

 and revolute. 



Leaves obovate-elliptic, subcordate__, 39. Q. greggii. 



Leaves broadly elliptic, round-based 40. Q. aculcingensis. 



Leaves usually very small (scarcely 2 cm. wide and 3 cm. long). 

 Leaves rugulose and revolute, rather blunt. 



Leaves deciduous 42. Q. micropliylla. 



Leaves evergreen or nearly so 43. Q. repanda. 



Leaves not rugose, conunonly acute 44. Q. intricata. 



EE. Leaves glabrate (scurfy-puberulent in Q. grisea), deciduous. 

 Leaves neither rugose nor coarsely veiny. 

 Leaves elliptic or oblong, very obtuse, blue-green. 



Leaves relatively narrow (1.5 cm. wide, 4 cm. long). Acorn striate. 



45. Q. engelmanni. 

 Leaves characteristically broader (3 cm. wide, 4.5 cm. long). 



46. Q. oblongifolia. 



Leaves very broadly elliptic, more or less puberulent 47. Q. grisea. 



Leaves lanceolate, acute, very small 49. Q. pringlei. 



Leaves not rugose, veiny beneath. Acorn short 19. Q. sororia. 



Leaves rugose, undulate, veiny beneath. Acorn elongate. 



17. Q. polymorpha. 

 EEE. Leaves canescent beneath, evergreen. 

 Leaves broadly elliptic, relatively large and usually obtuse. 



53. Q. oleoides. 

 Leaves lance-oblong, or elliptic-oblong and pungently acute. 



Cup turbinate or rounded ; acorn oblong-fusiform 54. Q. fusiforniis. 



Cup umbonate ; acorn conical 55. Q. brandegei. 



AAAA. Leaves, or many of them, pungently dentate or low-serrate. 

 Leaves canescent beneath. 



Cup turbinate or rounded ; acorn subfusiform 54. Q. fiisiformis. 



Cup umbonate : acorn conical • .55. Q. brandegei. 



Leaves not canescent. 



Leaves moderate, elliptic-obovate. 

 Peduncle elongate ; leaves rugose. 



Margin of leaves with crenate toothing ._35. Q. rugosa 



Margin of leaves with repand toothing 36. Q. reticulata. 



Margin variously entire to crenate-dentate 41. Q. diversifolia. 



Petluncle short; leaves only slightly rugose, puberulent. 



38. Q. arizonica. 

 Leaves commonly very small ; peduncle never veiy long. 

 Leaves ovate, the minute teeth near the apex, glabrous. 50. Q. toumeyi. 



Leaves polymorphous in outline and margin 51. Q. dumosa. 



Leaves elliptic-ovate, toothed throughout, pubescent. 



Teeth of leaves very short (1 mm.) ; pubescence rather woolly. 



44. Q. intricata. 

 Teeth long (3 to 4 mm.) ; pubescence rather velvety. 48. Q. pungens. 



