260 BETULA 



broader leaves than in adults, but at present they are very distinct and 

 striking in their stiff habit, fine foliage, and big buds. 



B. NAN A, Linn&us. DWARF BIRCH. 



A dwarf, neat-habited bush, 2 to 4 ft. high, branches erect, not warted, 

 clothed the first two years with minute down. Leaves round or occasionally 

 broader than long, never pointed, to \ in. diameter, conspicuously round- 

 toothed except at the base ; shining dark green above, prettily net-veined 

 beneath, smooth on both surfaces ; stalk ^W in. or less long, with a fringed 

 stipule at each side ; veins in two to four pairs. Fruiting' catkins erect, \ in. 

 long, shortly but distinctly stalked ; scales smooth, with lobes of about equal 

 length, the middle one the broadest. 



Native of northern latitudes in Europe (including N. Britain) and N. 

 America, usually inhabitating moist places on mountains. In gardens it is 

 useful for planting on the margins of streams and in moist places generally. 

 Among shrubby birches it is distinguished by its round-toothed, orbicular leaves, 

 and the absence of warts or glands on the shoots. 



B. INTERMEDIA, Thomas (B. alpestris, Fries\ is regarded as a hybrid 

 between B. nana and B. verrucosa. The leaves are much larger than in 

 nana, and more ovate, but retain much of the characteristic toothing of that 

 species. 



B. NIGRA, Linn&us. RlVER BlRCH. 



A tree of pyramidal form, 50 to 90 ft. high, with a trunk often forked low 

 down and, like the older branches, covered with large flakes of curling, blackish 

 bark, which gives it a picturesque ruggedness of aspect seen in no other species 

 except B. davurica ; bark of young trees whitish ; young shoots furnished with 

 pale, round warts, and very downy. Leaves diamond-shaped to ovate, always 

 wedge-shaped at the base, pointed, i^ to 3^ ins. long, f to 2j ins. wide, 

 conspicuously double-toothed or small-lobed ; glossy green above, glaucous 

 beneath ; downy only on the midrib and chief veins, finally smooth above ; 

 veins in six to nine pairs ; leaf-stalk downy, J to in. long. Male catkins 2 

 to 3 ins. long. Fruiting catkins I to i| ins. long, J in. thick, erect ; scales 

 downy. 



Native of the eastern United States ; introduced by Peter Collinson, in 

 1736. This is one of the most striking of birches, and its dark rugged trunk 

 affords a remarkable contrast to those of our native and other white species. 

 Although the trunk is sometimes undivided, a characteristic feature of the tree, 

 both wild and cultivated, is its division low down into two or three erect limbs. 

 In the south-eastern United States this birch inhabits the banks of ponds and 

 water-courses, often where the ground is inundated for several weeks at a time. 

 Sargent remarks that the seeds ripen early in the summer, and fall when the 

 water is at its lowest ; they immediately germinate in the moist, rich soil, and 

 thus secure a foothold by the time the waters return. It thrives quite well in 

 ordinary soil ; there is a tree 60 ft. high at Kew, far away from any water. 



B. PAPYRIFERA, Marshall. PAPER BlRCH. 



(B. papyraceu, Alton.') 



A tree 60 to 70 ft. high, with a rather thin, open head of branches, some- 

 times pendulous at the ends. Bark of the trunk one of the whitest among 

 birches, mostly very smooth, but coming away in thin, paper-like layers ; young 

 shoots warty, the hairs with which they are furnished when quite young soon 

 falling away. Leaves ovate, rounded, sometimes heart-shaped at the base, 



