BETULA 261 



slender-pointed; i to 3^ ins. long, two-thirds as wide; margins irregularly, 

 often doubly toothed, and hairy ; upper surface dull dark green, with scattered 

 hairs ; lower surface pale, downy in the axils of the veins, dotted with small 

 black glands ; stalks up to i in. long ; veins in six to ten pairs. Male catkins 

 up to 4 ins. long. Fruiting catkins drooping, about ii in. long, to in. 

 thick ; scales usually smooth, the lateral lobes broader than the middle one. 



Native of N. America, where it stretches right across the upper latitudes as 

 far north as Labrador and Hudson's Bay, and south to Iowa and Nebraska ; 

 introduced in 1750. It is the most widely spread of all American birches, and 

 the most useful tree of the inclement far north, providing the dwellers in those 

 regions with fuel. The bark is used for roofing, to make drinking utensils, and 

 especially canoes. In gardens it is valuable for the effect the vivid white trunk 

 produces. In this respect it is not more attractive than our native white birch, 

 nor has it the same delicate grace, its leaves being larger and less numerous ; 

 but the trunk remains white to a greater size. It varies very much, as might 

 be expected from its wide distribution, some trees having drooping branches, 

 others erect. 



Var. CORDIFOLIA, Fernald. A dwarf, even shrubby, form found on the 

 mountains of Eastern N. America. Leaves uniformly heart-shaped. 



B. KENAICA, Evans (B. papyrifera var. kenaica, ffenry}. This is an ally 

 of the paper birch, with small ovate leaves i to 2 ins. long ; irregularly, 

 coarsely, often doubly toothed, tapered at the base ; at first minutely downy 

 above, becoming smooth ; veins in five or six pairs ; stalk slender, f to I in. 

 long. The bark of the trunk is creamy white to reddish brown, and separates 

 into layers. The tree grows 30 or 40 ft. high, and is a native of the coast of 

 Alaska. Introduced to Kew in 1891. It differs from B. papyrifera in the fruit 

 scales being hairy on the margin, and in the smaller leaves. 



B. POPULIFOLIA, Marshall. GREY BlRCH. 



A tree 20 to 40 ft. high, with a rather thin, pyramidal head of branches, often 

 pendulous at the ends ; bark of the trunk grey-white, young shoots rough with 

 many warts, not downy. Leaves broadly ovate or triangular, broadly wedge- 

 shaped or truncate at the base, drawn out at the apex into a long, slender 

 point ; 2 to 3^ ins. long, 1 1- to 2^ ins. wide ; smooth and shining on both 

 surfaces, glandular above ; veins~ in six to nine pairs ; leaf-stalk slender, 

 dotted with black glands, f to i in. long. Male catkins 2 to 3^ ins. long. 

 Fruiting catkins f in. long, J in. diameter ; scales downy, with the side lobes 

 broader and more rounded than the middle one. 



Native of Eastern N. America ; introduced in 1750. The grey birch in its 

 own region plays much the same part as its ally the white birch does in Europe. 

 It occupies sterile and inclement regions, and is one of the first trees to find its 

 way back to land stripped, either by man or by fire, of its original forest 

 covering. It is short-lived, but according to Sargent performs a valuable 

 function in acting as a nurse for the seedlings of more durable trees It has 

 little to recommend it for gardens except its interest, having no merit that our 

 native birch does not possess in higher degree. The long stalk and drawn-out 

 apex of the leaf- and the absence of down from the younger parts, amply 

 distinguish it. 



B. PUBESCENS, Ehrhart. WHITE BlRCH. 



(B. alba, Linnceiis, in part.) 



A tree of small or medium size, occasionally 70 ft. or more high ; bark of 

 trunk white, peeling off in papery layers, eventually dark and rugged at the 



