



FOREST-TREES OP THE UNITED STATES. 29 



continent which attains a tree size. It grows from 20 to 30 feet high, 

 with a thick black bark. On the Pacific coast are several species which 

 become tree willows. 



No. 323. Salix nigra, var. Purshiana. Willow. Texas. 



No. 324. Salix longifolia, Muhl., var. California Long-leaved Willow. 

 California. 



No. 325. Salix Wrightiana, And. Wright's Willow. Texas. 



No. 326. Salix lasiolepis, Benth. Willow. California. 



No. 327. Salix lucida, Hook., var. California Shining Willow. Cal- 

 ifornia. 



No. 328. Populus tremuloides, Michx. American Aspen. Eastern 

 United States and Rocky Mountains. A small tree of the northern 

 border and Canada, also found on mountain-sides through the Kocky 

 Mountains. 



No. 329. Populus grandidentata, Michx. Great-toothed Aspen. 

 Eastern United States. This is a larger tree than the preceding, common 

 in the Northern States, and extending southward along the Alleghauy 

 Mountains. It much resembles the European Silver Poplar. 



No. 330. Populus monilifera, Ait. Cottonwood. Eastern United 

 States and Kocky Mountains. This and the next species of cottonwoods 

 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 and 

 western river-banks, extending even to the Pacific Ocean. The wood is 

 light and soft, much employed in some of the Western States for build- 

 ing purposes, and for inside work of houses, under the name of White- 

 wood and Cottonwood. 



No. 331. Populus angulata, Ait. Cottonwood. Southern States. 



No. 332. Populus heterophylla, L. Swamp Cottouwood. Eastern 

 United States. This species prevails in the Southern States, but extends 

 northward as far as Delaware and Southern Illinois. It is a large tree, 

 growing chiefly in swampy woods, and little valued. 



No. 333. Populus balsamifera, L. Balsam Poplar. Northern and 

 Western United States. This species grows mostly in northern latitudes, 

 being found in New England and Northern New York, also in the 

 Kocky Mountains. It is a large tree ; a variety of it is in cultivation. 



No. 334. Populus angustifolia, James. Willow-leaved Cottonwood. 

 Rocky Mountains. This is now considered to be a variety of the pre- 

 ceding. It is found principally along streams in the Kocky Mountains, 

 where it is called Cottonwood, sometimes Willow-leaved.Cottonwood. 



No. 335. Populus trichocarpa, Torr. Cottonwood. California, 



CONIFERS. 



No. 336. Pinus Banksiana, Lamb. Banks's Pine ; Scrub Pine. Wis- 

 consin to New England. This species is found from the northern 

 parts of the United States nearly to the Arctic Ocean, and from Labra- 

 dor to the Saskatchawan. In Wisconsin it becomes a middle-sized tree, 

 and is used for timber when the trees are found of sufficient size. 



No. 337. Pinus contorta, Dougl. Twisted pine. Kocky Mountains. 

 This tree is found in the Kocky Mountains from Colorado to Oregon. 

 It differs widely in regard to size in different localities. Near the Paci- 

 fic coast it is often low and scrubby, bearing cones at 5 feet high. In 

 Colorado it is found at an altitude of 7,000 feet, and attains a height of 

 50 feet. 



No, 338. Pinus contorta, Doug., var. Bolanderi. Bolandei^ Pine. 



