478 CUPULIFER^E. (OAK FAMILY.) 



Var. ambigua, Gray. (GRAY OAK.) Found along our northeastern bor- 

 ders to Lake Champlain and northward, figured and briefly characterized by 

 Michaux as with the foliage of Q. rubra and the fruit of Q. coccinea. It was 

 considered by Dr. Engelmann as a form of Q. rubra with cups hemispherical 

 or even turbinate. 



13. Q. pallistris, Du Roi. (SWAMP SPANISH or PIN OAK.) Cup flat- 

 saucer-shaped, sometimes contracted into a short scaly base or stalk, fine-scaled 

 (5 - 1" broad), very much shorter than the usually globose or depressed acorn, which 

 is 5 - 1" long ; leaves deeply pinnatifid with divergent lobes and broad rounded 

 sinuses. Low grounds; rather common, from Mass, to Del. and Md., west 

 to Minn., E. Kan., and Ark. 



<- *- Mature leaves soft-downy beneath; cup saucer-shaped, with a somewhat 

 top-shaped base, about half the length of the fully developed small acorn. 



14. Q. falcata, Michx. (SPANISH OAK.) Leaves grayish-downy or ful- 

 vous underneath, obtuse or rounded at base, 3 - 5-lobed above (sometimes entire) ; 

 the lobes prolonged, mostly narrow and more or less scythe-shaped, especially the 

 terminal one, entire or sparingly cut-toothed ; acorn globose, 4 - 5" long. 

 Dry or sandy soil, Long Island to Fla., and from S. Ind. to Mo. and Tex. A 

 \arge or small tree, extremely variable in foliage ; bark excellent for tanning. 



15. Q. ilicif61ia, Wang. (BEAR or BLACK SCRUB-OAK.) Dwarf (3- 

 8 high), straggling; leaves (2-4' long) thickish, obovate, wedge-shaped at 

 base, angularly about 5- (3 - 7-) lobed, white-downy beneath ; lobes short and tri- 

 angular, spreading ; acorn ovoid, globular, 5 - 6" long. Sandy barrens and 

 rocky hills, N. Eng. to Ohio and Ky. 



* # Leaves entire or with a few teeth (or somewhat 3 - 5-lobed at the summit), coria- 

 ceous, commonly bristle-pointed ; acorns globular, small (not over 6" long). 

 *- Leaves thick, widening or often much dilated upward and more or less sinuate 

 or somewhat 3 - 5-lobed ; acorns globular-ovoid. 



16. Q. aquatica, Walter. (WATER-OAK.) Leaves glabrous and shining , 

 obovate-spatulate or narrowly wedge-form, with a long tapering base and an often 

 obscurely 3-lobed summit, varying to oblanceolate ; cup saucer-shaped or hemi- 

 spherical. Wet grounds, around ponds, etc., Del. to the Gulf, and from Ky. 

 and Mo. to Tex. Tree 30-40 high ; running into many varieties, especially 

 southward ; the leaves on seedlings and strong shoots often incised or sinuate- 

 pinnatifid ; then mostly bristle-pointed. 



17. Q. nigra, L. (BLACK-JACK or BARREN OAK.) Leaves broadly wedge- 

 shaped, but sometimes rounded or obscurely cordate at the base, widely dilated 

 and somewhat 3-lobed (rarely 5-lobed) at the summit, occasionally with one or 

 two lateral conspicuously bristle-tipped lobes or teeth, rusty -pubescent beneath, 

 shining above, large (4 - 9' long) ; cup top-shaped, coarse-scaly ; acorn short- 

 ovoid. Dry sandy barrens, or heavy clay soil, Long Island to S. Minn., E. 

 Neb., and southward. A small tree (sometimes 30-40 high), of little value. 



-t- < Leaves not dilated upward, generally entire ; acorn globose. 



18. Q. imbricaria, Michx. (LAUREL or SHINGLE OAK.) Leaves Ian 

 ceolate-oblong , thickish, smooth, and shining above, downy underneath, the down 

 commonly persistent ; cup between saucer-shaped and top-shaped. Rich 

 woodlands, Penn. to Ga., west to S. Wise., Iowa, E. Neb., and N. Ark. 



