FAGACEAE 



349 



Leaf- blades with rounded broad sinuses ; lobes usually 



dilated near the apex. 11. Q. Schneckii. 



H Inner scales of the cup inflexed. 13. Q. Catesbaei. 



fj- Cup of the acorn turbinate or hemispheric. 



Acorns less than 15 mm. long ; cup hemispheric, less than 15 



mm. broad. 14. Q. Texana. 



Acorns over 20 mm. long ; cup turbinate, over 15 mm. broad. 15. Q. coccinca. 

 ** Leaf-blades pubescent beneath. 



Cup of the acorn turbinate : leaf-blades brown- or rusty-pubescent 



beneath. 16. Q.velutina. 



Cup of the acorn saucer-shaped : leaf-blades gray- or white-pubes- 

 cent beneath. 

 Large trees : leaves with lanceolate lobes. 



Leaf-blades rounded at the base ; lobes 3-5. 17. Q. digitata. 



Leaf-blades cuneate or truncate at the base ; lobes 5-13. 18. Q. pagodaefolia. 

 Shrubs or small trees : leaves with triangular lobes. 19. Q. nana. 



b. Leaves persistent. 20. Q. myrttfolia. 



B. Fruit maturing the first season : stems underground, the branches erect. 21. Q. pumila. 

 Leaf-blades, or their teeth or lobes without bristles (except on shoots): nuts often 



glabrous within. 

 Leaves persistent. 



Stems underground, the branches upright. 22. Q. minima. 



Stems erect. 



Leaf-blades prominently rugose-reticulated : cup of the acorn turbinate. 23. Q. geminata. 

 Leaf-blades not rugose-reticulated : cup of the acorn hemispheric (ex- 

 cept in Q.fustformis). 



Leaf-blades entire (or sometimes spiny-toothed on shoots): nuts fusi- 

 form to ovoid, over 18 mm. long and 9 mm. thick. 

 Acorns less than twice as long as thick ; cup hemispheric ; nut ovoid 



or oblong-ovoid. 24. Q. Virginiana. 



Acorns over twice as long as thick ; cup turbinate ; nut fusiform. 25. Q. fusiformis. 

 Leaf-blades sinuate-toothed : nuts cylinaric or oblong-cylindric, less 



than 18 mm. long and 9 mm. thick. 26. Q. undulata. 



Leaves deciduous. 



Leaf-blades entire or sinuate-undulate or merely lobed at the apex. 

 Cup of the acorn saucer-shaped. 



Leaf-blades pubescent beneath : cup thin and with a thin edge : nut of 



an obovoid type. 27. Q. Durandi. 



Leaf-blades glabrous : cup thick and with a thick corky edge : nut of 



an oblong or ovoid type. 28. Q. Laceyi. 



Cup of the acorn hemispheric. 



Young leaf-blades white beneath ; mature leaves glabrous, prominently 



lobed near the apex. 29. Q. austrina. 



Young leaf-blades tawny beneath ; mature leaves pubescent beneath, 



irregularly lobed of merely angulate. 30. Q. Chapmanii. 



Leaf-blades coarsely toothed or lobed. 

 Leaf-blades toothed or shallowly lobed. 

 Acorns sessile. 



Shrubs or small trees : leaf-blades mostly broadest above the middle. 

 Cup saucer-shaped : margins of the leaf-blades irregular. 



Leaf-blades pubescent beneath : cup thin and with thin edges: 



nut of an obovoid type. 31. Q. breviloba. 



Leaf-blades glabrous : cup thick and with a thick corky edge : 



nut of an oblong or ovoid type. 28. Q. Laceyi. 



Cup hemispheric : margins of the leaf-blades regular. 32. Q. prinoides. 



Tall trees : leaf-blades mostly broadest below the middle. 33. Q. acuminata. 



Acorns peduncled. 



Peduncles shorter than the petioles or about equalling them. 



Bark close, dark-colored : leaf-blades gray-tomentose beneath. 34. Q. Prinus. 

 Bark flaky, white: leaf-blades glabrous or white-tomentose 



beneath. 

 Leaf-blades leathery, densely pubescent beneath, with many 



lateral nerves and many relatively small teeth. 35. Q. Michauxii. 



Leaf-blades membranous, glabrous, with few lateral nerves 



and few large teeth. 36. Q. Brayi. 



Peduncles much longer than the petioles. 37. Q. platanoides. 



Leaf-blades prominently or deeply lobed. 



Mature leaf-blades more or less pubescent beneath : cup fully > as long 



as the nut. 



Upper scales of the cup awned, forming a fringe around the nut. 38. Q. macrocarpa. 

 Upper scales of the cup not awned. 



Acorn broader than high ; nut immersed in the cup or nearly so. 39. Q. lyrata. 

 Acorn longer than broad ; nut about % longer than the cup. 

 Leaf-blades obovate, gray or yellowish beneath, with 3-5 ample 



dilated lobes. 

 Leaf-blades with rounded upper lobes : cup 11-14 mm. 



broad : nut 12-14 mm. long. 40. Q. Margaretta. 



Leaf-blades with truncate or emarginate upper lobes : cup 



15-20 mm. broad ; nut 15-20 mm. long. 41. Q. minor. 



Leaf-blades cuneate, brown or yellowish brown beneath, with 



3-7 low never dilated lobes. 42. Q. Boyntonii. 



Mature leaf-blades glabrous and pale, or glaucous beneath: cup shallow. 43. Q. alba. 



1. Quercus FhSllos L. A tree, reaching a maximum height of about 25 m. and a 

 trunk diameter of 1 m., sometimes evergreen, the bark of the trunk nearly smooth. Leaf- 

 blades linear-oblong or narrowly-elliptic, varying to lanceolate or oblanceolate, 4-10 cm. 



