3. Sterile flower.

4. Branch with fertile catkins.

5. Fertile flower.

6. Fruiting branch.

7. Mature leaves.

=Salix nigra, Marsh.=

BLACK WILLOW

=Habitat and Range.=--In low grounds, along streams or ponds, river flats.

New Brunswick to western Ontario.

New England,--occasional throughout, frequent along the larger streams.

South to Florida; west to Dakota, Nebraska, Kansas, Indian territory, Louisiana, Texas, southern California, and south into Mexico.

=Habit.=--A large shrub or small tree, 25-40 feet high and 10-15 inches in trunk diameter, attaining great size in the Ohio and Mississippi valleys and the valley of the lower Colorado; trunk short, surmounted by an irregular, open, often roundish head, with stout, spreading branches, slender branchlets, and twigs brittle towards their base.

_S. nigra_, var. _falcata_, Pursh., covers about the same range as the type and differs chiefly in its narrower, falcate leaves.

=Bark.=--Trunk rough, in young trees light brown, in old trees dark-colored or nearly black, deeply and irregularly ridged, separated on the surface into thick, plate-like scales; branchlets reddish-brown; twigs bronze olive.

=Winter Buds and Leaves.=--Buds narrowly conical, acute. Leaves simple, alternate, appearing much later than those of _S. discolor_, 2-5 inches long, somewhat p.u.b.escent on both sides when young, when mature green and smooth above, paler and sometimes p.u.b.escent along the veins beneath; outline narrowly lanceolate, finely serrate; apex acute or ac.u.minate, often curved; base acutish to rounded or slightly heart-shaped; petiole short, usually p.u.b.escent; 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.

[Ill.u.s.tration: 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 a.s.sign 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. BRITTLE WILLOW.

=Habitat and Range.=--In low land and along river banks. Indigenous in southwestern Asia, and in Europe where it is extensively cultivated; introduced into America probably from England for use in basket-making, and planted at a very early date in many of the colonial towns; now extensively cultivated, and often spontaneous in wet places and along river banks, throughout New England and as far south as Delaware.

=Habit.=--Tree often of great size; attaining a maximum height of 60-90 feet; head open, wide-spreading; branches except the lowest rising at a broad angle; branchlets reddish or yellowish green, smooth and polished, very brittle at the base. In 1890 there was standing upon the Groome estate, Humphreys Street, Dorchester, Ma.s.s., a willow of this species about 60 feet high, 28 feet 2 inches in girth five feet from the ground, with a spread of 110 feet (_Typical Elms and other Trees of Ma.s.sachusetts_, p. 85).

=Bark.=--Bark of the trunk gray, smooth in young trees, in old trees very rough, irregularly ridged, sometimes cleaving off in large plates.

=Winter Buds and Leaves.=--Buds about 1/3 inch long, reddish-brown, narrow-conical. Leaves simple, alternate, 2-6 inches long, smooth, dark green and shining above, pale or glaucous beneath and somewhat p.u.b.escent when young; outline lanceolate, glandular-serrate; apex long-ac.u.minate; tapering to an acute or obtuse base; leafstalk short, glandular at the top; stipules half-cordate when present, soon falling.

=Inflorescence.=--April to May. Catkins appearing with the leaves, spreading, stalked,--sterile 1-2 inches long; stamens 2-4, usually 2; filaments distinct, p.u.b.escent below; ovary abortive: fertile catkins slender; stigma nearly sessile; capsule long-conical, smooth, short-stalked.

=Horticultural Value.=--Hardy throughout New England; grows best near streams, but adapts itself readily to all rich, damp soils. A handsome ornamental tree when planted where its roots can find water, and its branches s.p.a.ce for free development. Readily propagated from slips.

SALIX ALBA, L.

WHITE WILLOW.

=Habitat and Range.=--Low, moist grounds; along streams. Probably indigenous throughout Europe, northern Africa, and Asia as far south as northwestern India. Extensively introduced in America, and often spontaneous over large areas.

New Brunswick, Nova Scotia, and Ontario.

New England,--sparingly throughout.

South to Delaware; extensively introduced in the western states.

=Habit.=--A large tree, 50-80 feet in height; trunk usually rather short and 2-7 feet in diameter; head large, not as broad-spreading as that of _S. fragilis_; branches numerous, mostly ascending.

=Bark.=--Bark of trunk in old trees gray and coa.r.s.ely ridged, in young trees smooth; twigs smooth, olive.

=Leaves.=--Leaves simple, alternate, 2-4 inches long, _silky-hairy on both sides when young, when old still retaining more or less p.u.b.escence, especially on the paler under surface_; outline narrowly lanceolate or elliptic-lanceolate, glandular-serrate, tapering to a long pointed apex and to an acute base; leafstalk short, usually without glands; stipules ovate-lanceolate, soon falling.

=Note.=--Var. _vitellina_, Koch., by far the most common form of this willow; mature leaves glabrous above; twigs _yellow_. Var. _caerulea_, Koch.; mature leaves bluish-green, glabrous above, glaucous beneath; twigs _olive_.

=Inflorescence.=--April to May. Catkins appearing with the leaves, slender, erect, stalked; scales linear; stamens 2; filaments distinct, hairy below the middle; stigma nearly sessile, deeply cleft; capsule glabrous, sessile or nearly so.

=Horticultural Value.=--Hardy throughout New England; grows best in moist localities; extensively cultivated to bind the soil along the banks of streams. Easily propagated from slips.

JUGLANDACEae. WALNUT FAMILY.

=Juglans cinerea, L.=