The preceding description does not agree with that of Betula lutea exactly, and has been drawn to cover the specimens at hand from Indiana which the author has from Allen, Crawford, Lagrange, Lake, Marshall, Porter and Steuben Counties. It has recently been reported from White County by Heimlich.[29] He says: "Specimens were taken from two trees about two miles south of Buffalo near the water's edge of the river." The writer has visited this locality and found here, and also on the island above the bridge a little farther down the river, Betula nigra, but could not find Betula lutea. Since Heimlich did not report Betula nigra, which unmistakably occurs here, I assume he has confused the two species. It is very local in its distribution, and appears to be confined to swamps, borders of lakes, and streams in the extreme northern part of the State. It has not been seen south of the northern end of the State, except a few small trees found clinging to the walls of the cliffs of a ravine about one mile east of Taswell in Crawford County. The walls of this ravine are about 25 meters high; associated with it were a few trees of hemlock, and on the top of the cliffs, laurel (Kalmia latifolia).
Large trees of this species in Indiana are usually from 4-6 dm. in diameter and about 15 m. high. The number in any one station is usually few, although there were formerly patches where it was plentiful. Van Gorder[30] reports for Noble County Betula lenta which should be transferred to this species, and he says: "There is a marsh of several acres of birch in Section 15 of York Township." The largest area now known is that contained in the large tamarack swamp near Mineral Springs in Porter County. In this swamp are found tamarack and white cedar. It was in this swamp that the writer found a peculiar form of birch which has been determined as Betula Sandbergi. Since this species[31] is recognized as a hybrid of Betula papyrifera and Betula pumila variety glandulifera, and the last parent of this hybrid is not found in the vicinity, a discussion of this form is not presented. In the immediate vicinity are found only Betula lutea and Betula pumila. Betula papyrifera is found about a mile distant to the south. It is assumed that this form is a cross between Betula lutea and Betula pumila.
2. Betula populifòlia Marshall. Gray or White Birch. [Plate 33.] A small tree; bark a chalky-white, not separating into thin layers, inner bark orange, on the trunks of old trees nearly black; shoots at first covered with numerous glands, becoming smooth and yellowish or reddish-brown; leaves generally long-deltoid, average blades 3-6 cm. long, usually long taper-pointed, truncate or nearly so at the base, irregularly double-serrate, slightly pubescent on the veins when young, soon becoming glabrous; fertile catkins 1.5-3 cm. long and about 7 mm. in diameter; bracts of eastern trees differ from those of Indiana trees which are about 3-4 mm. long, lobed to about 1/3 of the distance from the apex, lateral lobes the largest and strongly divaricate, puberulent on the back; seed strongly notched at the apex; nut slightly obovoid; wings much broader than the nut.
Distribution.—Nova Scotia west to southern Ontario and south to Delaware and Pennsylvania. In Indiana it has been reported from Lake, Laporte, Porter, St. Joseph and Tippecanoe Counties. There may be some doubt about the Tippecanoe record, since many of the older records were made from cultivated trees. The numbers of the species in Indiana were always limited. It is not able to meet changed conditions and it has already almost disappeared from our area. I was told that formerly this species was found all about a lake in Laporte County, but it has all died out. Its appearance in Indiana is peculiar since it is not found west of us, or north in Michigan or east in Ohio. This small group of trees near Lake Michigan is three or four hundred miles from the nearest of their kind.
Remarks.—This species is called white and gray birch. The largest tree seen in Indiana was about 2 dm. in diameter and 13 m. high.
BETULA POPULIFOLIA Marshall. White or Gray Birch. (× 1/2.)