Honey Locust Three-thorned Acacia
=Habitat and Range.=--In its native habitat growing in a variety of
soils; rich woods, mountain sides, sterile plains.
Maine,--young trees in the southern sections said to have been
produced from self-sown seed (M. L. Fernald); New Hampshire and
Vermont,--introduced; Massachusetts,--occasional; Rhode
Island,--introduced and fully at home (J. F. Collins); Connecticut,--
reported. Probably sparingly naturalized in many other places in New
Spreading by seed southward; indigenous along the western slopes of
the Alleghanies in Pennsylvania; south to Georgia and Alabama; west
from western New York through southern Ontario (Canada) and
Michigan to Nebraska, Kansas, Indian territory, and Texas.
=Habit.=--A medium-sized tree, reaching a height of 40-60 feet and a
trunk diameter of 1-3 feet; becoming a tree of the first magnitude in
the river bottoms of Ohio, Kentucky, and Tennessee; trunk dark and
straight, the upper branches going off at an acute angle, the lower
often horizontal, both trunk and larger branches armed above the axils
with stout, sharp-pointed, simple, three-pronged or numerously branched
thorns, sometimes clustered in forbidding tangles a foot or two in
length; head wide-spreading, very open, rounded or flattish, with
extremely delicate, fern-like foliage lying in graceful planes or
masses; pods flat and pendent, conspicuous in autumn.
=Bark.=--Trunk and larger branches a sombre iron gray, deepening on old
trees almost to black; yellowish-brown in second year's growth; season's
shoots green, marked with short buff, longitudinal lines; branchlets
=Winter Buds and Leaves.=--Winter buds minute, in clusters of three or
four, the upper the largest. Leaves compound, once to twice pinnate,
both forms often in the same leaf, alternate, 6 inches to 1 foot long,
rachis abruptly enlarged at base and covering the winter buds: leaflets
18-28, 3/4-1-1/4 inches long, about one-third as wide, yellowish-green
when unfolding, turning to dark green above, slightly lighter beneath,
yellow in autumn; outline lanceolate, oblong to oval, obscurely
crenulate-serrate; apex obtuse, scarcely mucronate; base mostly rounded;
leafstalks and leaves downy, especially when young.
=Inflorescence.=--Early June. From lateral or terminal buds on the old
wood, in slender, pendent, greenish racemes scarcely distinguishable
among the young leaves; sterile and fertile flowers on different trees
or on the same tree and even in the same cluster; calyx somewhat
campanulate, 3-5-cleft; petals 3-5, somewhat wider than the sepals, and
inserted with the 3-10 stamens on the calyx: pistil in sterile flowers
abortive or wanting, conspicuous in the fertile flowers. Parts of the
flower more or less pubescent, arachnoid-pubescent within, near the
=Fruit.=--Pods dull red, 1-1-1/2 feet long, flat, pendent, and often
twisted, containing several flat brown seeds.
=Horticultural Value.=--Hardy throughout New England, grows in any
well-drained soil, but prefers a deep, rich loam; transplants readily,
grows rapidly, is long-lived, free from disease, and makes a picturesque
object in ornamental plantations, but is objectionable in public places
and highly finished grounds on account of the stiff spines, which are a
source of danger to pedestrians, and also on account of the long
strap-shaped pods, which litter the ground. There is a thornless form
which is better adapted than the type for ornamental purposes. The type
is sometimes offered in nurseries at a low price by the quantity.
Propagated from seed.
1. Winter buds.
2. Winter buds with thorns.
3. Flowering branch.
4. Sterile flower, enlarged.
5. Flowering branch, flowers mostly fertile.
6. Fertile flower, enlarged.
7. Fruiting branch.
8. Leaf partially twice pinnate.
=Robinia Pseudacacia, L.=