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Florida 4-H Forest Ecology

Florida 4-H Forest Ecology

Identifying Characteristics

Size/Form: Black locust is a medium tree that reaches heights of 60 to 82 feet. It has an open crown.
Leaves: The leaves are pinnately compound, alternate, and deciduous. They generally have 7 to 9 leaflets on a central stalk 20 to 30 inches long with a terminal leaflet. Leaflets are slightly longer than they are wide, ½ to 2 inches long by ½ to 1 inch wide. Leaflets are oval or elliptical in outline. The lower leaflet surface is lighter and covered with short hairs along the midrib. The leaflet margins are entire. The leaflets turn yellow in autumn. A pair of spines at the base of the leaf vary in size.
Twigs: Twigs zigzag and are somewhat stout and angular. Color is red-brown and numerous lenticels are visible. Paired spines exist at each leaf scar, but may be absent on older or slow-growing twigs.
Bark: The bark is light brown to gray. A young tree has smooth bark but as the tree ages the bark becomes furrowed with dark brown, thick, and interlacing ridges.
Flowers: Flowers are perfect and borne in loose drooping racemes 4 to 5 inches long. Cream-white in color, they are about 1 inch long, and bear fragrant nectar.
Fruit: The fruit is an oblong legume measuring 2 to 4 inches in length and about ½ inch wide. Several flat, smooth, and reddish-brown legumes remain on the tree throughout winter. The inside of the fruit contains small pea-sized, hard and dark seeds.
Similar Trees on the Florida 4-H Forest Ecology Contest List:

Several others on our list also have alternate, pinnately-compound leaves. 

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