Betula. | LXXIII. AMENTACEZ. 405 
the nuts, which are small and seed-like, flat, surrounded by a scarious 
wing. 
Seated genus, confined to the northern hemisphere, and not reach- 
ing the tropics. 
Tree, with broadly ovate, usually pointed leaves . ; ; - . 1. B. alba. 
Shrub with small, orbicular leaves . y ; , f . i . 2 B. nana. 
1. B. alba, Linn. (fig. 912). Common B:—An elegant tree, with 
slender, often gracefully drooping branches, the white bark of the 
trunk readily peeling off in layers. Leaves usually broadly ovate, 
taper-pointed, and toothed, but varying from rhomboidal to triangular 
or broadly cordate, often trembling on their slender stalks like those 
of the Aspen, glabrous and shining, with minute gldndular dots when 
young. Male catkins drooping, 1 to 2 inches long ; the females shortly 
stalked, about 6 inches long when in flower. Fruiting catkins 1 to 1$ 
inches, the scales wedge-shaped, fully 2 lines long, broadly 3-lobed. 
In woods, in northern and central Europe, north Asia, and North 
America, more limited to mountain districts in southern Europe. 
Extends all over Britain. FV. spring, before the leaves are fully out. [In 
the ordinary B. alba the side lobes of the fruiting bracts are spread- 
ing; in var. glutinosa they are more erect ; in the latter the twigs are 
glabrous or pubescent, and the leaves more or less glutinous. ] 
2. B. nana, Linn. (fig. 913). Dwarf B.—Usually a small shrub, but 
sometimes attains 20 feet. Leaves very shortly stalked, nearly orbi- 
cular, seldom above half an inch long, and not pointed. Catkins small 
and sessile, the males oblong or shortly cylindrical, the females scarcely 
above 38 lines long. Fruiting catkins about 6 lines long, the scales 
not so thin, nor so deciduous as in B. alba. 
In moors and bogs, in northern Europe, Asia, and America, and in 
the mountains of central Europe. Not uncommon in the Highlands 
of Scotland, but rare in the north of England, and unknown in Ireland. 
Fl. spring. 
oe 
IV. CARPINUS. HORNBEAM. 
Flowers monececious, the males in cylindrical catkins, with broad, 
sessile scales. Stamens about 12 within each scale, without inner scales 
or perianth ; the anther-cells distinct, on very short, forked filaments. — 
Female catkins slender, the scales lanceolate and deciduous. Flowers 
2 within each scale, each enclosed in a hairy, unequally 3-lobed inner 
scale. Perianth combined with the ovary at the base, with a minute 
toothed border. Ovary 2-celled, with a pendulous ovule in each cell. 
Styles 2. Fruiting catkin much elongated, the inner scales enlarged 
into long, leafy, unequaily 3-lobed bracts, each enclosing at its base 
a small nut. 
There are but very few European, Asiatic, or North American species, 
differing slightly from each other in the shape of the fruiting bracts. 
1. C. Betulus, Linn. (fig. 914). Common H.—A small tree, with 
numerous short, slender branches. Leaves stalked, ovate, pointed, 
doubly toothed, with parallel veins diverging from the midrib, usually 
downy in their axils underneath. Male catkins sessile, about 14 inches 
long, less drooping than in the allied genera; the anthers crowned by 
