516 FAGACEAE. 
+t Leaves 3-5-lobed above the middle or entire, obovate or spatulate in outline. 
Leaves obovate-cuneate, brown-floccose beneath, * 8. O. Marylandica. 
Leaves spatulate, glabrous both sides. 9. QO. nigra. 
TTT Leaves entire, oblong, lanceolate or linear-oblong (sometimes lobed in no. 11). 
Leaves linear-oblong, green and glabrous on both sides. 10. QO. Phellos: 
Leaves oblong, glabrous, dark green and shining above. 11. O. laurtfolia. 
Leaves oblong or lanceolate, brown-tomentulose beneath. 12. O. imbricaria. 
% % Leaves or their lobes not bristle-tipped, deciduous; acorns maturing in autumn of first year. 
+ Leaves pinnatifid 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. QO. minor. 
Leaves white-tomentulose beneath; acorn depressed-globose. | 15. QO. lyrata. 
Upper scales awned, forming a fringe around the acorn. 16. QO. macrocarpa. 
+? Leaves crenate or dentate, not lobed. 
Fruit peduncled. 
Peduncle much longer than petioles; leaves white-tomentulose beneath. 17. Q. pla/anotdes. 
Peduncle equalling or shorter than the petioles; leaves gray-tomentulose beneath. 
Teeth of the leaves acute or mucronulate. 18. O. Michauxii. 
Teeth of the leaves rounded. 19. QO. Prinus. 
Fruit sessile. 
Tall tree; leaves oblong or lanceolate. 20. O. acuminata. 
Shrub or low tree; leaves oval or obovate. 21. O. prinoides. 
% % % Leaves entire (rarely with a few bristle-tipped lobes), evergreen. 22. O. Virginiana. 
1. Quercus rubra L. Red Oak. (Fig. 1228.) 
Quercus rubra I. Sp. Pl. 996. 1753. 
O. ambigua Michx. f. Hist. Arb. Am. 2:120. pl. 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’—S’ long, 3/-6’ wide, dull green above, paler 
beneath, sinuses rounded, lobes triangular-lanceo- 
late, tapering from a broad base to an acuminate 
apex, 1-4-toothed or entire, teeth and apices tipped 
with filiform bristles; petioles 114’-3’ long; styles 
slender, spreading; fruit maturing the second 
autumn; cup saucer-shaped, its base flat or slightly 
convex, 8/’/-12’’ broad, bracts ovate or ovate-lan- 
ceolate, obtuse or the upper acute, appressed; acorn 
ovoid, about 1’ 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- 
grained; color light reddish-brown; weight per cubic 
foot 41 lbs. May-June. Acorns ripe Oct.—Nov. 
Quercus rubra runcinata A. DC. Prodr. 16: Part 2, 60. 1864. 
Leaf-lobes nearly entire; acorn 1s’ high. Near St. Louis. Perhaps a hybrid with OQ. digi/a/a. 
2. Quercus palustris DuRoi. Swamp Oak. Pin Oak. (Fig. 1229.) 
QO. palustris DuRoi, Harbk. 2: 268. pl. 5. f. 4. 1772. ‘ i 5 
A forest tree, maximum height about 120° and K A Yk, \ J 
trunk diameter 5°, the lower branches deflexed; SQ 
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, 1-4-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 lbs. May-June. Acorns ripe Sept.-Oct. 
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