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Black Locust (robinia Pseudacacia)

Distinguishing characters: The *bark* of the trunk is _rough_ and

_deeply ridged_, as shown in Fig. 81. The *buds* are _hardly

noticeable_; the twigs sometimes bear small spines on one side. The

leaves are large, compound, and fern-like. The individual leaflets

are small and delicate.

Form and size: The locust is a medium-sized tree developing a slender

straight trunk when grown alongside of others; see Fig. 82.

Range: Canada and United States.

Soil and location: The locust will grow on almost any soil except a wet,

heavy one. It requires plenty of light.

Enemies: The _locust borer_ has done serious damage to this tree. The

grubs of this insect burrow in the sapwood and kill the tree or make

it unfit for commercial use. The _locust miner_ is a beetle which is

now annually defoliating trees of this species in large numbers.

Value for planting: It has little value for ornamental planting.

Commercial value: Though short-lived, the locust grows very rapidly. It

is extremely durable in contact with the soil and possesses great

strength. It is therefore extensively grown for fence-posts and

railroad ties. Locust posts will last from fifteen to twenty years.

The wood is valuable for fuel.

Other characters: The _flowers_ are showy pea-shaped panicles appearing

in May and June. The _fruit_ is a small pod.

Other common names: _Yellow locust_; _common locust_; _locust_.

Comparisons: The _honey locust_ (_Gleditsia triacanthos_) can be told

from the black locust by the differences in their bark. In the honey

locust the bark is not ridged, has a sort of dark iron-gray color

and is often covered with clusters of stout, sharp-pointed thorns as

in Fig. 83. The fruit is a large pod often remaining on the tree

through the winter. This tree has an ornamental, but no commercial


Tree Studies

How To Identify Trees
Group I The Pines
The White Pine (pinus Strobus)
The Pitch Pine (pinus Rigida)
The Scotch Pine (pinus Sylvestris)
Group Ii The Spruce And Hemlock
The Norway Spruce (picea Excelsa)
Hemlock (tsuga Canadensis)
Group Iii The Red Cedar And Arbor-vitae
Red Cedar (juniperus Virginiana)
Arbor-vitae; Northern White Cedar (thuja Occidentalis)
Group Iv The Larch And Cypress
The European Larch (larix Europaea)
Bald Cypress (taxodium Distichum)
Group V The Horsechestnut, Ash And Maple
The Horsechestnut
The White Ash (fraxinus Americana)
Sugar Maple (acer Saccharum)
Silver Maple (acer Saccharinum)
Red Maple (acer Rubrum)
Norway Maple (acer Platanoides)
Box Elder (acer Negundo)
Group Vi Trees Told By Their Form: Elm, Poplar, Gingko And Willow
American Elm (ulmus Americana)
Lombardy Or Italian Poplar (populus Nigra, Var Italica)
Gingko Or Maidenhair Tree (gingko Biloba)
Weeping Willow (salix Babylonica)
Group Vii Trees Told By Their Bark Or Trunk: Sycamore, Birch, Beech,
Blue Beech, Ironwood, And Hackberry
The Sycamore Or Plane Tree (platanus Occidentalis)
Gray Or White Birch (betula Populifolia)
American Beech (fagus Americana)
Blue Beech Or Hornbeam (carpinus Caroliniana)
Hackberry (celtis Occidentalis)
Group Viii The Oaks And Chestnut
White Oak (quercus Alba)
Black Oak (quercus Velutina)
Red Oak (quercus Rubra)
Pin Oak (quercus Palustris)
Chestnut (castanea Dentata)
Group Ix The Hickories, Walnut And Butternut
Shagbark Hickory (hicoria Ovata)
Mockernut Hickory (hicoria Alba)
Black Walnut (juglans Nigra)
Group X Tulip Tree, Sweet Gum, Linden, Magnolia, Locust, Catalpa,
Dogwood, Mulberry And Osage Orange
Tulip Tree (liriodendron Tulipifera)
Sweet Gum (liquidambar Styraciflua)
American Linden (tilia Americana)
The Magnolias