516 FAGACEAE. 



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



Leaves obovate-cuneate, brown-floccose beneath. 8. Q. Marylandica. 



Leaves spatulate, glabrous both sides. 9. Q. nigra. 



ttt Leaves entire, oblong, lanceolate or linear-oblong (sometimes lobed in no. in. 

 Leaves linear-oblong, green and glabrous on both sides. 10. Q. Phellos. 



Leaves oblong, glabrous, dark green and shining above. n. Q. laurifolia. 



Leaves oblong or lanceolate, brown-tomentulose beneath. 12. Q. imbricaria. 



** Leaves or their lobes not bristle-lipped, deciduous; acorns maturing in autumn of first year. 



t Leaves pinnatind or pinnately lobed. 



Mature leaves pale, or glaucous and glabrous beneath; cup shallow. 13. Q. alba. 



Mature leaves tomentulose 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. 14. Q. minor. 



Leaves white-tomentulose beneath; acorn depressed-globose. 15. Q. lyrata. 



Upper scales awned. forming a fringe around the acorn. 16. Q. macrocarp 



"ft Leaves crenate or dentate, not lobed. 

 Fruit peduncled. 



Peduncle much longer than petioles; leaves white-tomentulose beneath. 17. Q. platanoides 

 Peduncle equalling or shorter than the petioles; leaves gray -tomentulose beneath. 



Teeth of the leaves acute or mucronulate. 18. Q. Michauxii. 



Teeth of the leaves rounded. 19. Q. Prinus. 



Fruit sessile. 



Tall tree; leaves oblong or lanceolate. 20. Q. acuminata. 



Shrub or low tree; leaves oval or obovate. 21. Q. prinoides. 



* -X- Leaves entire (rarely with a few bristle-tipped lobes), evergreen. 22. Q. Virginian 



i. Quercus rubra L,. Red Oak. (Fig. 1228.) 



Quercus rubra L. Sp. PI. 996. 1753. 



Q. ambigua Michx. f. Hist. Arb. Am. 2: 120. pi. 24. 1812. 



A large forest tree, with a maximum height of 

 about 140, and a trunk diameter of 7, the bark 

 dark gray, slightly roughened. Leaves oval or some- 

 what obovate in outline, deciduous, when mature 

 glabrous, or pubescent in the axils of the veins be- 

 neath, 4 / -8 / long, 3 / -6 / wide, dull green above, paler 

 beneath, sinuses rounded, lobes triangular-lanceo- 

 late, tapering from a broad base to an acuminate 

 apex, i-4-toothed or entire, teeth and apices tipped 

 with filiform bristles; petioles i^'-s' long; styles 

 slender, spreading; fruit maturing the second 

 autumn; cup saucer-shaped, its base flat or slightly 

 convex, 8 // -i2 // broad, bracts ovate or ovate-lan- 

 ceolate, obtuse or the upper acute, appressed; acorn 

 ovoid, about i / long, 2-4 times as long as the cup. 



Nova Scotia to Ontario and Minnesota, south to 

 Florida, Kansas and Texas. Wood hard, strong, coarse- 

 2 grained; color light reddish-brown; weight per cubic 



foot 41 Ibs. May-June. Acorns ripe Oct. -Nov. 

 Quercus riibra runcinata A. DC. Prodr. 16: Part 2, 60. 1864. 

 Leaf-lobes nearly entire; acorn %' high. Near St. Louis. Perhaps a hybrid with Q. digitata. 



2. Quercus palustris DuRoi. Swamp Oak. Pin Oak. (Fig. 1229.) 



Q. palustris DuRoi, Harbk. 2: 268. pi. 5. f. 4. 1772. 



A forest tree, maximum height about 120 and 

 trunk diameter 5, the lower branches deflexed; 

 bark brown, rough when old. Leaves broadly 

 oblong or obovate in outline, deeply pinnatifid, 

 sometimes almost to the midrib, bright green 

 glabrous and shining above, duller, glabrous or 

 with tufts of hairs in the axils of the veins be- 

 neath, 3 / -5 / long, the lobes oblong, lanceolate 

 or triangular-lanceolate, divergent, i-4-toothed 

 or entire, teeth and apices tipped with filiform 

 bristles; styles slender; fruit maturing in the sec- 

 ond autumn; cup saucer-shaped, 4 // -6 // broad, 

 base flat, bracts triangular-ovate, acute or obtuse, 

 appressed; acorn subglobose or ovoid, 4 // -7 // 

 high, often striate, 2-3 times as long as the cup. 



In moist ground, Massachusetts to Wisconsin, 

 Delaware and Arkansas. Wood hard, very strong, 

 coarse-grained; color light brown ; weight per cubic 

 foot 43 Ibs. May-June. Acorns ripe Sept. -Oct. 



