ULMACEAE 71 



3. Q. velutiua Lam. Black Oak. Leaves as in Q. Texana but 

 usually pubescent below along the veins even when mature, and 5-sided 

 in outline, sometimes smooth : cup hemispheric, its scale somewhat squar- 

 rose, yellowish floocose-pubescent : acorn 6"-12'' long, about twice the 

 length of the cup. — A common tree, especially in the southern part. 

 April-May. A form, common especially in the southern part, with 

 leaves and petioles floocose-pubescent even in age and leaves intermediate 

 between this species and Q. Marylandica is probably distinct. 



4. Q. Marylandica Muenoh. Black Jack Oak. Leaves short- 

 petioled, wedge-shaped at base, 3-5-lobed at the summit, the lobes 

 toothed, rusty-pubescent beneath : cup S^'-S" broad, deep, pubescent, 

 half shorter than the acorn. — Common in barrens in the southern part. 

 April-May. 



5. Q. imbricaria Michx. Shingle Oak. Leaves lanceolate-oblong, 

 thick, shining above and downy beneath, entire : cup h"-'l" broad, acorn 

 subglobose. — Common along streams. April-May. 



6. Q. minor (Marsh.) Sarg. Post Oak. Leaves broadly obovate, 

 yellowish-pubescent beneath, pinnatifid into 3-7 broad-toothed lobes : 

 cup W-W broad, hemispheric, 1-3J times shorter than the acorn. — Com- 

 mon in barrens, especially in the southern part. April-May. 



7. Q. alba L. White Oak. Leaves obovate, nearly glabrous, deeply 

 sinuate-pinnatifid into 3-9, obtuse, often toothed lobes : cup T'-V)" broad, 

 depressed hemispherical. l-SJ times shorter than the acorn. — A common 

 forest tree throughout. April-May. 



8. Q. macTocarpa Michx. Bur Oak. Leaves broadly ovate, white- 

 pubescent beneath, irregularly lobed or pinnate : cup S'^-SO" wide, deep, 

 the scales subulate tipped and forming a mossy fringe, sometimes cover- 

 ing the acorn. — Common in rich soil. April-May. 



9. Q. platanoides (Lam.) Sudw. Swamp White Oak. Leaves ob- 

 ovate, wedge-shaped at base, sinuate-crenate above, white-downy beneath: 

 cup long-pedunoled (2-5 times length of petiole), hemispheric: acorn 

 oblong-ovoid. — In low grounils around Sheffield and south of Oak Grove. 

 April-May. 



10. Q. acuminata (Michx.) Sarg. Chestnut OAK. Leaves oblong- 

 lanceolate, acute or acuminate, sharply toothed : petioles &'-Vi," long : 

 cup hemispheric, b"-%" broad, peduncled or sessile : acorn ovoid, twice 

 as high as the cup. — A tall tree, common throughout. April-May. 



11. Q. prinoides Willd. Chinquapin Oak. A shrub 2°-]5° high, 

 very close to the last, but leaves broader and less toothed, on peti- 

 oles V-V long. — Common in barrens, especially in the southern part. 

 April-May. 



Family 32. ULMACEAE Mirbel. 



Trees with alternate, stipulate leaves and clustered or solitary flowers. 

 Calyx of 3-9 sepals. Stamens opposite sep ils. Ovary superior, 1 celled. 

 Ovule one, pendulous. Styles or stigmas two. Fruit a samara or drupe. 



