ouped in forests.

=Bark.=--Easily detachable in broad sheets and separable into thin,
delicately colored, paper-like layers, impenetrable by water, outlasting
the wood it covers. Bark of trunk and large branches chalky-white when
fully exposed to the sun, lustreless, smooth or ragged-frayed, in very
old forest trees encrusted with huge lichens, and splitting into broad
plates; young trunks and smaller branches smooth, reddish or grayish
brown, with numerous roundish buff dots which enlarge from year to year
into more and more conspicuous horizontal lines. The white of the bark
readily rubs off upon clothing.

=Winter Buds and Leaves.=--Buds small, ovate, flattish, acute to
rounded. Leaves simple, alternate, 3-5 inches long, two-thirds as wide,
dark green and smooth above, beneath pale, hairy along the veins,
sometimes in young trees thickly glandular-dotted on both sides; outline
ovate, ovate-oblong, or ovate-orbicular, more or less doubly serrate;
apex acute to acuminate; base somewhat heart-shaped, truncate or obtuse;
leafstalk 1-2 inches long, grooved above, downy; stipules falling early.

=Inflorescence.=--April to May. Sterile catkins mostly in threes, 3-4
inches long: fertile catkins 1-1-1/2 inches long, cylindrical,
slender-peduncled, erect or spreading; bracts puberulent.

=Fruit.=--Fruiting catkins 1-2 inches long, cylindrical, short-stalked,
spreading or drooping: nut obovate to oval, narrower than its wings;
combined wings butterfly-shaped, nearly twice as wide as long.

=Horticultural Value.=--Hardy throughout New England; prefers a
well-drained loam or gravelly soil, but does fairly well in almost any
situation; young trees rapid growing and vigorous, but with the same
tendency to grow irregularly that is shown by the black and yellow
birches; transplanted without serious difficulty; not offered by many
nurserymen, but may be obtained from northern collectors.

[Illustration: PLATE XXXIV.--Betula papyrifera.]

1. Leaf-buds.
2. Flower-buds.
3. Flowering branch.
4. Sterile flower, front view.
5. Fertile flower, front view.
6. Scale of fertile flower.
7. Fruiting branch.
8. Fruit.

=Alnus glutinosa, Medic.=

EUROPEAN ALDER.

This is the common alder of Great Britain and central Europe southward,
growing chiefly along water courses, in boggy grounds and upon moist
mountain slopes; introduced into the United States and occasionally
escaping from cultivation; sometimes thoroughl