99 



COTTONWOOD. 



Populus deltoides, Marshall. 



FORM A large tree usually 50-75 ft. high but may reach a height of more than 100 ft. 

 with a diamoter of 6 feet. Trunk tapering, continuous, sometimes clean for a considerable 

 distance from the ground. Crown usually high and pyramidal. Lower lateral branches 

 horizontal, while most of the upper branches are decidedly ascending. 



BARK On old trunks thick, ashy-gray, roughened by long deep furrows which are usually 

 longitudinally parallel, and often connect with one another. Rather thin, smooth, and greenish- 

 yellow on younger trunks. 



TWIGS Stout, "usually yellow tinged with green or brown, round or ridged below the buds; 

 covered with large, longitudinally-elongated lenticels; pith white and angular. 



BUDS Alterrate, large, resinous, glossy, smooth, chestnut-brown, covered with numerous 

 bud-scales which are sticky, resinous on the interior and smooth on the exterior. Terminal buds 

 often 5-angled and larger than lateral ones; lateral buds usually divergent and often recurved. 



LEAVES Alternate, simple, broadly deltoid, truncate to wedge-shaped at base, acuminate at 

 apex, coarsely serrate on margin, 3-5 inches long, thick, deep shining green above, pale 

 green below. Leaf-stalks laterally flattened. 



LEAF-SCARS Alternate, large, lunate, elevated, depressed on upper margin, sometimes 3-lobed; 

 with 3 bundle-scars. Stipule-scars dark and conspicuous. 



FLOWERS Appear about March or April. Staminate and pistillate flowers occur on different 

 trees. The staminate are arranged in drooping aments 3-4 inches long and are densely 

 flowered; the pistillate, in drooping aments 2J-3J inches long and sparsely flowered. 



FRUIT A drooping ament bearing dark green, 3-4-valved capsules which contain small 

 seeds surrounded with a mat of long white hairs. Fruiting aments longer than in the other 

 native species, 8-12 inches. 



WOOD Diffuse-porous; with very indistinct rays; pores in early wood visible to unaided 

 eyes; heartwood dark brown; sapwood wide and white; wood is soft, warps easily, and is 

 ditflcult to split. Weighs about 23 Ibs. per cubic foot. Used for paper pulp, boxes, crates, 

 berry boxes, pails, and tubs. 



DISTINGUISHING CHARACTERISTICS The Cottonwood, also known as Carolina Poplar, 

 Cotton Tree, and Whitewood may readily be distinguished at any season of the year by its 

 lateral branches which have a tendency to ascend like the Lombardy Poplar (Fig. 36), 

 and by its yellowish twigs which often have prominent ridges running down from the leaf- 

 scars. The bnds are larger, more resinous, and often more flattened than those of any other 

 member of this genus; usually divergent and often incurved. The leaves are very character- 

 istic since they have laterally flattened leaf -stalks, are deltoid in outline, truncate at the 

 base and long-pointed at the apex. The pores in the early wood are visible to the unaided 

 eye while those of the American and Large-toothed Aspens are not visible. 



RANGE Quebec and Ontario south to Florida, west to the Rocky Mountains. 



DISTRIBUTION IN PENNSYLVANIA Natural distribution is very limited. Reported from 

 Presque Isle, Erie county and from Lancaster county. Locally escaped cultivation. Planted 

 extensively for ornamental purposes and in a few plantations for forestry purposes. 



HABITAT Prefers rich moist soil, like banks of streams, borders of lakes, and semi- 

 swamps. 



IMPORTANCE OF THE SPECIES The Cottonwood is planted extensively as an ornamental 

 tree but as such it has few merits except its rapid growth, rather attractive form In winter, 

 and the pleasant balsamic odor from its coated, young, developing leaves. It is well adapted 

 to wet locations and may be planted where other more valuable trees will not grow. It grows 

 rapidly, and produces an excellent pulp-wood. This tree is known to grow 5 feet in a single 

 year and 40 feet in 10 years. Cuttings taken from trees and placed in the ground grow very 

 readily. When planted in the streets its roots often lift pavements, and clog drains and 

 sewers. Not adapted for street planting. 



