olor_, 2-5 inches
long, somewhat pubescent on both sides when young, when mature green and
smooth above, paler and sometimes pubescent along the veins beneath;
outline narrowly lanceolate, finely serrate; apex acute or acuminate,
often curved; base acutish to rounded or slightly heart-shaped; petiole
short, usually pubescent; stipules large and persistent, or small and
soon falling.

=Inflorescence.=--April to May. Appearing with the leaves from the axils
of the short, lateral shoots, in catkins, sterile and fertile on
different trees, stalked,--sterile spreading, narrowly cylindrical;
calyx none; corolla none; bracts entire, rounded to oblong, villous,
ciliate; stamens about 5: fertile catkins spreading; calyx none; corolla
none; bracts ovate to narrowly oblong, acute, villous; ovary
short-stalked, with two small glands at its base, ovate-conical,
sometimes obovate, smooth; stigmas 2, short.

=Fruit.=--Fertile catkins drooping: capsules ovate-conical,
short-stemmed, minutely granular; style very short: seeds numerous.

=Horticultural Value.=--Hardy in New England; grows rapidly in all
soils, particularly useful in very wet situations; seriously affected by
insects; occasionally offered in nurseries; transplanted readily;
propagated from cuttings.

[Illustration: PLATE XXI.--Salix nigra.]

1. Winter buds.
2. Branch with sterile catkins.
3. Sterile flower, side view.
4. Sterile flower, front view.
5. Branch with fertile catkins.
6. Fertile flower, side view.
7. Fertile flower, front view.
8. Fruiting branch.
9. Fruit enlarged.

=Salix fragilis and Salix alba.=

The _fragilis_ and _alba_ group of genus _Salix_ gives rise to puzzling
questions of determination and nomenclature. Pure _fragilis_ and pure
_alba_ are perfectly distinct plants, _fragilis_ occasional, locally
rather common, and _alba_ rather rare within the limits of the United
States. Each species has varieties; the two species hybridize with each
other and with native species, and the hybrids themselves have varietal
forms. This group affords a tempting field for the manufacture of
species and varieties, about most of which so little is known that any
attempt to assign a definite range would be necessarily imperfect and
misleading. The range as given below in either species simply points out
the limits within which any one of the various forms of that species
appears to be spontaneous.

=Salix fragilis, L.=

CRACK WILLOW.