olive-color or reddish 9.

=I.= Branches not very twiggy; leaves all alternate 11, 12.

=F.= Leaves very long and slender, almost linear 14.

[Illustration: S. nigra]

1. =Salix nigra=, Marsh. (BLACK WILLOW.) Leaves narrowly lanceolate,
tapering at the ends, serrate, smooth except on the petiole and midrib,
green on both sides; stipules small (large in var. _falcata_), dentate,
dropping early. Branches very brittle at base. A small tree, 15 to 35
ft. high, with rough black bark. Common along streams, southward, but
rare in the northern range of States.

[Illustration: S. amygdaloides.]

2. =Salix amygdaloides=, Anderson. (WESTERN BLACK WILLOW.) Leaves 2 to 4
in. long, lanceolate or ovate-lanceolate, attenuate-cuspidate, pale or
glaucous beneath, with long slender petioles; stipules minute and soon
falling. A small tree, 10 to 40 ft. high, from central New York
westward. It is the common Black Willow of the streams of Ohio to
Missouri.

[Illustration: S. fragilis.]

3. =Salix fragilis=, L. (BRITTLE WILLOW. CRACK-WILLOW.) Leaves
lanceolate, taper-pointed, smooth, glaucous beneath (slightly silky when
young), serrate throughout; stipules half heart-shaped, usually large.
Branches smooth and polished, very brittle at base. A tall (50 to 80 ft.
high) handsome Willow, with a bushy head and salmon-colored wood;
cultivated from Europe for basket-work, and extensively naturalized.
Many varieties, hybrids between this species and the next, are very
common. Among them may be mentioned the following:

Var. _decipiens_, with dark-brown buds; var. _Russelliana_, with more
slender, brighter, and more sharply serrate leaves, the annual shoots
silky-downy toward autumn; var. _viridis_, with tough, pendulous
branchlets, and firmer, bright green leaves.

[Illustration: S. alba.]

4. =Salix alba=, L. (WHITE WILLOW.) Leaves lanceolate or
elliptical-lanceolate, pointed, serrate, covered more or less with white
silky hairs, especially beneath; var. _caerulea_ has nearly smooth
leaves, at maturity of a bluish tint; stipules small and quite early
deciduous. Catkins of flowers long and loose, on a peduncle; stamens
usually 2; stigmas nearly sessile, thick, and recurved. May, June. A
quite large tree, 50 to 80 ft. high, with thick, rough bark, usually
having yellow twigs (var. _vitellina_); introduced from Europe and now
quite common throughout. Branches ve