The Pod-Bearers - Family Leguminosae

THE POD-BEARERS - FAMILY LEGUMINOSAE Trees of high ornamental and timber value. Leaves com pound (except in Cercis), alternate, deciduous. Flowers sweet, pea-like, or regular. Fruit, a pod.

KeY TO IMPORTANT GENERA AND SPECIES A. Foliage simple; flowers rosy, pea-like.

I. Genus CERCIS, Linn.

B. Leaves heart shaped. (C. Canadensis) REDBUD BB. Leaves kidney shaped. (C. Texensis) TEXAS REDBUDAA. Foliage compound.

B. Leaves twice compound; flowers regular. C. Branches thorny; foliage fleecy.

2. Genus GLEDITSIA, Linn.

D. Pods 12 to 18 inches long, pulpy, many-seeded.

(G. trzacantbos) HONEY LOCUST DD. Pods 4 to 5 inches long, without pulp, many seeded. (G. Texana) TEXAN HONEY LOCUST DdD. Pods oval, I to 2-seeded, without pulp.

(G. aquatica) WATER LOCUST CC. Branches thornless; foliage and pods coarse.

3. Genus GYMNOCLADUS, K. Koch.

(G. dioicus) KENTUCKY COFFEE TREE BB. Leaves once compound; flowers pea-like, showy, in racemes, pods thin.

C. Leaves with spiny stipules.

4. Genus ROBINIA, Linn.

D. Blossoms white; shoots smooth.

(R. Pseudacacia) LOCUST DD. Blossoms pink; shoots hairy.

E. Shoots clammy. (R. viscosa) CLAMMY LOCUST EE. Shoots not clammy.

(R. Neo-Mexicana) NEW MEXICAN LOCUST CC. Leaves without spiny stipules; flowers white, in loose clusters.

5. Genus CLADRASTIS, Raf. (C. lulea) YELLOW-wooD The family Leguminosx, to which our pod-bearing trees belong, is one of vast size and economic importance, and of world-wide distribution. There are nearly 45o genera and over 7,000 species. Peas, beans, lentils, clover—all plants that bear simple, 2-valved pods after the flowers—are included. By this sign they are easily recognisable when in fruit. Besides food stuffs, the pod-bearers yield rubber, balsams, oils, dyestuffs, good timber, and a long list of ornamental plants. The grass family, which includes the chief forage and grazing plants, the grains and sugar cane, is the only one that ranks higher than the legumes in service to the human family.

The pod-bearers are the only plants that have the power to abstract nitrogen from the air and store it in their stems and roots. The rotting of these parts restores to the soil that particular plant food which is most commonly lacking and the costliest to replace. The cheapest way to put nitrogen into the soil is to plough under green crops of clover, cowpeas, or other legumes.

They improve the texture and therefore the moisture-holding capacity of the soil; commercial fertilisers do not. Legumes grow on poor soil and make it rich.

American pod-bearing trees belong to several different genera, with one or more species in each. With few exceptions they have handsome pinnate foliage, and showy flowers in drooping clusters. These characters, combined with an admirable form, give these trees prominence as ornamentals wherever they will grow. Their pods are often highly decorative in summer and winter. The thorns of certain species give the trees character and distinction. Several valuable lumber trees are included in the family. In North American forests seventeen genera of pod-bearers are native. These include over thirty species. Beside these, several exotic species are met with in cultivation.

i. Genus CERCIS, Linn.

The genus Cercis, including seven species of shrubs and trees, is distributed in Asia, Europe and America. We have two tree forms and one shrubby species, native to California.

Red Bud, Judas Tree (Cercis Canadensis, Linn.)—A dainty tree, sometimes 40 to 5o feet high, oftener much smaller, with broad, flat head of slender, smooth, thornless, angular branchlets. Bark reddish brown, furrowed deeply and closely, broken into small, scaly plates; twigs brown or grey. Wood heavy, hard, close grained, weak, red-brown. Buds inconspicuous, axillary, scaly, blunt. Leaves simple, entire, broadly heart shaped or ovate, alternate, deciduous, on long, slender, smooth petioles which are enlarged at apex; autumn colour yellow. Flowers, April, before the leaves, in axillary fascicles, pea-like, 1 inch long, rose pink to purplish; numerous, conspicuous. Fruit a pod, thin, pointed, flat, smooth, lustrous, purplish, stalked, 2 to 3 inches long. many-seeded. Preferred habitat, borders of streams, under other trees. Distribution, New Jersey to western Florida, Alabama, Mississippi, Texas; Ontario to Nebraska and south. Maximum size, Arkansas to Texas. Uses: Important hardy ornamental tree. Grown in Europe. Flowers sometimes eaten as a salad.