BETULACE.E 205 



A tree 20-30 high, with a trunk 12'-18' in diameter, usually divided 1 or 2 above the 

 ground into 3 or 4 stout upright stems 4'-5' thick, slender pendulous often much contorted 

 branches forming a narrow round-topped symmetrical head, and slender branchlets dark 

 green and coated with hoary tomentum when they first appear, dark red-brown and pu- 

 bescent during their first summer, becoming light cinnamon-brown, glabrous, and lustrous 

 in the winter, and ultimately ashy gray. Winter-buds ovoid, dark brownish red, about |' 

 long. Bark internally bright orange color, ' thick, separating into loose hanging plate- 

 like scales light gray slightly tinged with red, and l'-2' long and wide. Wood light red- 

 dish brown, with thin sapwood. 



Distribution. On the southern slope of the canon of the Colorado River in Coconino 

 County, Arizona, at altitudes of 6000-7000 above the sea (Hance trail, seventy miles 

 north of Flagstaff); in the canon of Oak Creek, south of Flagstaff (P. Lowell); and on 

 Grand River, Utah (Moab, Grant County, M . E. Jones}. 



3. BETULA L. Birch. 



Trees, with smooth resinous bark marked by long longitudinal lenticels, often separat- 

 ing freely into thin papery plates, becoming thick, deeply furrowed, and scaly at the base of 

 old trunks, short slender branches more or less erect and forming on young trees a narrow 

 symmetrical pyramidal head, becoming horizontal and often pendulous on older trees, 

 tough branchlets, short stout spur-like 2-leaved lateral branchlets much roughened by 

 the crowded leaf-scars of many years, and elongated winter-buds covered by numerous 

 ovate acute scales, and fully grown and bright green at midsummer. Leaves open and 

 convex in the bud, often incisely lobed; stipules ovate and acute or oblong-obovate, scarious. 

 Flowers in 3-flowered cymes, the lateral flowers of the cyme subtended by bractlets adnate 

 to the base of the scale of the ament; staminate aments long, pendulous, solitary or clus- 

 tered, appearing in summer or autumn in the axils of the last leaves of a branchlet or near 

 the ends of short lateral branchlets, erect and naked during the winter, their scales in the 

 spring broadly ovate, rounded, short-stalked, yellow or orange-color below the middle and 

 dark chestnut-brown and lustrous above it; staminate flowers composed of amembrana- 

 ceous 4-lobed calyx often 2-lobed by suppression, the anterior lobe obovate, rounded at apex, 

 as long as the stamens, much longer than the minute posterior lobe, and of 2 stamens in- 

 serted on the base of the calyx, with short 2-branched filaments, each branch bearing an 

 erect half-anther; pistillate aments oblong or cylindric, terminal on the short spur-like 

 lateral branchlets, their scales closely imbricated, oblong-ovate, 3-lobed, light yellow, often 

 tinged with red above the middle, accrescent, becoming brown and woody at maturity, 

 and forming sessile or stalked erect or pendulous short or elongated strobiles usually ripen- 

 ing in the autumn, deciduous with the nuts from the slender rachis; calyx of the pistillate 

 flower 0; ovary sessile, compressed, with styles stigmatic at apex. Nut minute, oval or 

 obovoid, compressed, bearing at the apex the persistent stigmas, marked at the base by 

 a small pale scar, the outer coat of the shell produced into a marginal wing interrupted at 

 the apex. 



Betula is widely distributed from the Arctic circle to Texas in the New World, and to 

 southern Europe, the Himalayas, China, and Japan in the Old World, some species form- 

 ing great forests at the north, or covering high mountain slopes. Of the twenty-eight or 

 thirty species now recognized twelve are found in North America; of these nine are trees. 

 Of exotic species the European and Asiatic Betula pendula Roth, in a number of forms is a 

 common ornamental tree in the northern states, where several of the Birch-trees of eastern 

 Asia also flourish. Many of the species produce wood valued by the cabinet-maker, or used 

 in the manufacture of spools, shoe-lasts, and other small articles. The thin layers of the 

 bark are impervious to water and are used to cover buildings, and for shoes, canoes, and 

 boxes. The sweet sap provides an agreeable beverage. 



Betula is the classical name of the Birch-tree. 



