124 Proceedin^^s of the Ohio State Academy of Science 



- *. Populns dilatata Ait. Lombardy Poplar. A spire-like 

 tree of rapid growth. Commonly planted for ornament. 



5. Populus deltoides Marsh. Cottonwood. A larg-c tree 

 of ver}^ rapid growth, with rough, deeply furrowed, brown bark 

 when old. Bark of young trees grayish-green and rather smooth. 

 The giant of the poplars. Petiole much flattened laterally causing 

 the leaves to rustle in the wind. Leaves glabrous, broadly del- 

 toid-ovate, abruptly acuminate at the apex, crenulate, truncate 

 at the base, 4-7 in. long. Wood light and soft and very durable 

 if kept in the dry; used for building lumber, light boxes, paper 

 pulp, sugar and flour barrels, cracker boxes, crates and wooden 

 ware ; also a good fuel wood. A most useful and ornamental tree 

 of very rapid growth if planted in ravines and low places. In cities 

 only staminate trees should be planted. In moist soil, especially 

 on the banks and flood plains of creeks and rivers. Quebec to 

 Man., south to Fla. and Kan. Ohio. 



6. Populus grandidentata Mx. Largetooth Aspen. A 

 tree with smooth, greenish-gray bark. Leaves tomentose when 

 young, glabrous when mature, short-acuminate, obtuse or trun- 

 cate at the base, 2-4 in. long. \A'ood soft and white ; used for 

 paper pulp. In rich moist soil. X. S. to Out. and Minn., south 

 to N. J. and Ohio, and in the Alleghanies to Tenn. 



7. Populus tremuloides Mx. American Aspen. A 

 slender tree with light green, smooth bark. Leaves usually short- 

 acuminate at the apex, finely crenulate, truncate, rounded or sub- 

 cordate at the base, 1-3 in. broad. Petioles very slender, caus- 

 ing the leaves to quiver and rustle in the slightest breeze. Wood 

 white and soft ; used for making coarse paper. In moist or dry 

 soil. Newf. to Alaska, south to N. J., Ohio, Ky., and Neb. ; in 

 the Rocky Mts. to Mexico and to Lower Cal. 



12. Salix L. AVillow. 



Trees or shrubs with buds having a single outer scale. 

 Flowers in aments ; fruit a capsule ; seeds with long cottony hairs. 

 Leaves sometimes with glands on the petiole or at the base of the 

 blade and with gland tipped teeth. Twigs self-pruned by means 



