SALICACEA.
Salix nigra. Black Willow. Eastern United States. This is almost the only willow of the eastern portion of the continent which attains a tree size. It grows from twenty to thirty feet high. with a thick black bark. On the Pacific coast are several species which become tree willows.
Salix nigra, var. Purshiana. Willow. Texas.
S. Longzfolia, var. California Long-Leaved Willow. California S. Wrightiana. Wright's Willow Texas.
S. losiolepis. Willow. California.
S. lucida, var. California Shining Willow. California.
Penult's trernuloides. American Aspen. Eastern United States and Rocky Mountains. A small tree of the north ern border and Canada, also found on tbe mountain sides through the Rocky mountains.
P. grandidentata. Great Toothed Aspen. Esstens United States. This is a larger tree than the preceding, common in the Northern States, and extending south ward along the Alleghanymountains. It much resembles the Europesn Silver Poplar.
P. monilifera. Cottonwood. Eastern United States and Rocky Mountains. This and the next species of cot tonwoods have a wide range throughout most parts of the United States. Some botanists consider them to be but forms of one species. They are large, rapidly growing trees, particularly abundant in the prairie regions a ud Western river banks, ext tiding even to the Pacific Crean. The wood is light and soft, much employed in
some of the Western States fur building purposes, and for Inside work of houses, under the name of Whitewood and Cottonwood.
P. angulata. Cottonwood. Southern States.
P.heterophylla. Swamp Cottonwood. Eastern United States. This species prevails in the Southern States, but extends northward as far as Delaware and Southe, n Illinois. It is a large tree, growing chiefly in swampy woode, and little valued.
P. balsarnifera. Balsam Poplar. Northern and West ern United States. This species grows mostly in northern latitudes, being found in New England and Northern New York, also in the Rocky mountains. It is a large tree ; a variety of it iS in cultivation.
P. angustifolia, James. Willow leaved Cottonwood. Rocky Mountains. Thiele now considered to be a variety of the preceding. It is fouhd principally along streams in the Rocky mountains, where it is called Cottonwood, nometimes Willow-leaved Cottonwood.
P. trichocarpa. Cottonwood. California.