Distribution.—Nova Scotia west to northern Minnesota and south to the Ohio River, and along the Alleghany Mountains to South Carolina. Found throughout Indiana, except we have no authentic records for Gibson[11] and Posey[12] Counties. In the northern part of Indiana it is found in great colonies about lakes, etc. or rarely a few trees on the crests of gravel and sand ridges. In southern Indiana it is found in the "knob" area in small colonies on the tops of the ridges associated with scrub pine and chestnut oak and is rarely found in low ground in this part of the State.
Remarks.—This species is too rare to be of much economic importance. It could be most profitably used for excelsior and pulp wood.
POPULUS GRANDIDENTATA Michaux. Large-toothed Aspen. (× 1/2.)
5. Populus tremuloìdes Michaux. Quaking Aspen. [Plate 19.] A straight narrow tree up to 3 dm. in diameter, usually about 1-5 dm. in diameter; bark usually smooth, greenish-white or gray, on older trees becoming rough or fissured, and turning darker; shoots glabrous or with a few hairs, turning reddish-brown the first season, later to a gray; leaves of sprouts and very small trees usually ovate with a cordate base and two or three times as large as leaves of older trees; mature leaves on older trees variable, glabrous, the prevailing type has a bluish-green leaf which is widely ovate or nearly orbicular, 3-7 cm. long, truncate or slightly rounded at the base, usually abruptly short-pointed at apex, finely and regularly serrate, the unusual type of leaf is thinner, yellow-green, ovate, 2/3 as wide as long, rounded or wedge-shaped at base, gradually tapering to a point at the apex, otherwise as the prevailing form; stamens 6-12; capsules about 6 mm. long, on stalks about 1 mm. long; wood light, soft and weak.
Distribution.—One of the most widely distributed of North American trees. It ranges from Labrador south to Pennsylvania, thence southwest to northern Mexico, and then north to northern Alaska. It is found at sea level and at elevations of 10,000 feet. There are records of its occurrence in all parts of Indiana. In all of its Indiana stations it grows only in low ground about lakes, swamps, ponds, low places between sand dunes, and along streams. In many places in the lake region it is found in almost pure stands over small areas.
Remarks.—In Indiana this species is not of sufficient size and abundance to be of much economic importance.