SUPPLEMENT. 309 



Birch), the blue-green foliage of which is easily dis- 

 tinguished from that of other birches, especially at a 

 distance. The leaves are thin, attenuated, generally 

 broad-ovate, lopsided or else quite regular in outline, 

 wedge-shaped at the base or often slightly scolloped, 

 and smooth on both sides, the steins long and slender. 

 Fertile catkins pendent. Branchlets and leaves always 

 perfectly smooth, the larger branches slender and sup- 

 ple, more or less drooping. Bark lustrous, from buff- 

 white to a pale copper tone deepening into bronze. 

 Eocky uplands and mountain-sides throughout the far 

 northwest to Alaska, and locally common south to 

 Maine, New Hampshire, Vermont, Illinois, etc. 



Birch, Canoe, White, or Paper. Betula alba. All the 

 branchlets in this typical species and its varieties are 

 covered with fine hairs, so also are the under sides of 

 the young leaves (except in the shrub var. minor). 

 Branches and branchlets uprising, never drooping; 

 leaves ovate, rounded, or wedge-shaped at the base, 

 scarcely two and a half inches long at maturity, olive 

 green and smooth above, much paler, glandular-dotted, 

 and with a few hairs on the veins beneath, and cleanly 

 but unevenly double-toothed. A modest-sized tree com- 

 mon in the north, and extending south into New Eng- 

 land and the region of the Great Lakes. In progressive 

 gradations it passes into the far more common var. 

 papyrifera described on p. 93, a larger tree with larger 

 leaves and whiter bark. Its southern limit is Pennsyl- 

 vania, north Iowa, Nebraska, Wyoming, and Washing- 

 ton. The rather rare or at least local var. cordifolia is 

 characterized by broad ovate leaves distinctly heart- 

 shaped at the base, and fine-hairy or woolly on the veins 

 beneath. A northern variety found only in upland 



