122 » FLORA OF PHILADFLPHIA. 



Cup of the acorn turbinate or henuspherie. 



inner bark gray to reddish ; leaves deeply lobed. 



Leaves shining both sides, lobed to near the midrib. 



3. Q. coccinea. 

 Leaves dull and paler beneath ; acorn ovoid. 



4. Q. horealis. 

 Inner bark orange. 5. Q. velutina. 



Leaves white or gray-tonientose beneath. 



Large trees; leaf-lobes lanceolate to linear-lanceolate, long. 



6. Q. digitata. 

 SShrub or low tree ; leaf -lobes triangular-ovate, short. 



7. Q. nana. 



Leaves 3-5 lobed above the middle or entire, obovate or spatulate in outline. 



Leaves obovate, crenate, brown-floccose beneath. 8. Q. Mnrylaiidica. 



With characters intermediate between Q. Marylandica and Phellos. 



9. Q. BudMni. 

 Leaves spatulate, glabrous both sides. 10. Q. nigra. 



Leaves entire, oblong, lanceolate or linear -oblong. 



Leaves linear-oblong, green and glabrous on both sides. 11. Q. Phellos. 

 With characters intermediate between Q. rubra and Q. Phellos. 



12. Q. heterophylla. 

 Leaves oblong or lanceolate, brown-tomentose beneath. 13. Q. imbricaria. 



B. Leaves or their lobes not bristle-tipped, decidiious ; acorns maturing in 

 autumn of first year. 



Leaves pinnatifid or pinnately lobed. 



Mature leaves pale or glaucous and glabrous beneath; cup shallow. 



14. Q. alba. 

 Mature leaves tonientulose beneath; cup one-third to fully as long as 



the acorn. 

 Upper scales of the cup not awned. 



Leaves yellowish-brown tomentulose beneath ; acorn ovoid. 



15. Q. minor. 

 Leaves white-tomentulose beneath; acorn depressed-globose. 



16. Q. lyrata. 

 Upper scales awned, forming a fringe around the acorn. 



17. Q. macrocarpa. 



Leaves crenate or dentate, not lobed. 



Fruit peduncled. 



Peduncle much longer than petioles; leaves white-tomentulose beneath. 



18. Q. platanoides. 

 Peduncle equalling or shorter than the petioles; leaves gray-tomentu- 



lose beneath. 

 Bark white, flaky. 19. Q. Michauxii. 



Bark close. 20. Q. Prinus. 



Fruit sessile or nearly so. 



Tall trees. 21. Q. acuminata. 



Shrub or low tree; leaves oval or obovate. 22. Q. prinoides. 



1. QUERCUS RUBRA L. Red Oak. M. p. 333. Eich or poor soil. Early 



summer. 



2. QuERCUS PALUSTRis DvL Roi. Swamp Oak, Pin Oak. M. p. 333. Low 



ground. Early summer. 



3. QuERCus COCCINEA Wang. Scarlet Oak. M. p. 333. Moist or dry soil. 



Early smnmer. 



