COTTONWOOD IN THE MISSISSIPPI VALLEY. 1l 
of the Mississippi River into the Great Plains region, where it is 
found at altitudes as high as 9,000 feet, but is confined to the river 
banks, 
BOTANICAL CHARACTERISTICS. 
Populus deltoides Marsh is usually known merely as cottonwood, 
but in certain sections is variously spoken of as Carolina poplar, 
yellow cottonwood, white cottonwood, big cottonwood, cotton tree, 
broadleaved cottonwood, Vermont poplar, necklace poplar, and still 
other local names. - It has been introduced into Europe, where it is 
variously termed the Swiss white poplar, the black Italan poplar, 
the Canadian poplar, ete. 
The leaves, which are usually oe 3 to 6 inches long and equally 
board, are more or less triangular in shape, sharply pointed, 
prominently veined, and edged with glandular incurved teeth. 
The leaves on the more vigorous shoots in the top of the tree 
are frequently more than twice the length of the others. When 
crushed they emit a pleasant balsamic odor. The leafstalks are 
flattened on the sides for most of their length, but become more 
round near their junction with the twig. Cottonwood has long, 
pointed, greenish or reddish-green winter buds, which are very res- 
inous and are somewhat flattened. The bark on the younger stems 
and branches is comparatively thin and of a. light grayish-yellow 
color, tinged with green, but on the trunks of older trees becomes 
rough, thick, and deeply furrowed and is dark grayish in color. 
In cottonwood the male and female flowers are borne on different 
trees (dicecious). Seed therefore is borne only on female individuals, 
whereas the male trees are always barren. The flowers bloom from 
February to April, according to the latitude, and always before the 
leaves are out. They occur in long pendulous catkins. The female 
catkins mature toward the last of April or May, even before the 
leaves have attained full growth, at which time the 3 or 4 valved 
capsules open and shed large quantities of “ cottony ” seed that is 
carried far and wide by the wind. To this abundant production of 
downy-ccated seed cottonwood owes its name as well as the disfavor 
in which it is sometimes held for lawn and street planting. It is 
a very simple matter, however, to overcome this objection by propa- 
gating only male trees. (See fig. 1.) 
Populus deltoides is easily distinguished from the swamp cotton- 
wood (Populus heterophylla Linn.), which has somewhat the same 
range, by its distinctly triangular-shaped leaves and its thicker, more 
closely attached bark. In the western extension of its range cotton- 
wood grows with norrow-leaved cottonwood (P. angustifolia James), 
which is readily disinguished by its narrow lapceolate leaves. 
