BugwoodWiki Article

black locust
Robinia pseudoacacia L.

Overview

Appearance
Robinia pseudoacacia is a deciduous tree that, while native to parts of the United States, has spread to and become invasive in other parts of the country. Trees grow from 40-100 ft. (12-30 m) in height. Trees grow upright in forests, but develop an open growth form in more open areas. The bark of black locust is light brown, rough, and becomes very furrowed with age.
Foliage
Leaves are pinnately compound with 7-21 small, round leaflets per leaf. Leaflets are 1.5 in. (4 cm) long. A pair of long, stipular spines is found at the base of most leaves.
Flowers
Flowering occurs in the spring, when showy, fragrant, white to yellow flowers develop in 8 in. (20.3 cm) long clusters.
Fruit
The flowers give way to a smooth, thin seed pod that is 2-4 in. (5.1-10.2 cm) in length.
Ecological Threat
Robinia pseudoacacia is native to the Southern Appalachians, the Ozarks, and other portions of the Midsouth, but is considered an invasive species in the prairie and savanna regions of the Midwest where it can dominate and shade those open habitats.

General Description:

Black locust is a large deciduous tree and sometimes a shrub, growing up to 25 m tall. Narrow brittle branches form a round or oblong head. Older trees have furrowed dark brown bark with flat topped ridges. Leaves are alternate, pinnately compound and have 7 to 21 leaflets. The thin leaflets are elliptic or rounded with a mucronate tip, and are dark green above, pale beneath. Fragrant white flowers have a yellow blotch on the uppermost petal, and are born in drooping racemes. The glabrous pods are 5 to 10 cm long, and contain four to eight seeds. Seedlings and sprouts exhibit juvenile growth characterized by rapid growth and heavy thorns. More description is provided in Fernald (1950), Stephens (1973), and Barnes and Wagner (1981).

Resources

Selected Images


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black locust
Robinia pseudoacacia
Tree(s)
Jan Samanek
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black locust
Robinia pseudoacacia
Tree(s)
Chris Evans
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black locust
Robinia pseudoacacia
Feature(s)
Leslie J. Mehrhoff
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black locust
Robinia pseudoacacia
Flower(s)
Leslie J. Mehrhoff
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black locust
Robinia pseudoacacia
Flower(s)
Bill Cook
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black locust
Robinia pseudoacacia
Flower(s)
Jan Samanek
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black locust
Robinia pseudoacacia
Flower(s)
Paul Wray
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black locust
Robinia pseudoacacia
Flower(s)
Leslie J. Mehrhoff
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black locust
Robinia pseudoacacia
Flower(s)
Jan Samanek
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black locust
Robinia pseudoacacia
Fruit(s)
Jan Samanek
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black locust
Robinia pseudoacacia
Fruit(s)
Paul Wray
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black locust
Robinia pseudoacacia
Fruit(s)
Leslie J. Mehrhoff
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black locust
Robinia pseudoacacia
Feature(s)
Leslie J. Mehrhoff
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black locust
Robinia pseudoacacia
Foliage
Jan Samanek
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black locust
Robinia pseudoacacia
Foliage
Paul Wray
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Robinia pseudoacacia
Foliage
James H. Miller
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black locust
Robinia pseudoacacia
Bark
Paul Wray
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black locust
Robinia pseudoacacia
Seed(s)
Steve Hurst

Maps


EDDMapS Distribution - This map is incomplete and is based only on current site and county level reports made by experts, herbaria, and literature. For more information, visit www.eddmaps.org

EDDMapS Distribution

State Regulated List - This map identifies those states that list this species on their regulated list. For more information, visit Invasive.org

State Regulated List

Taxonomic Rank

Kingdom: Plantae
Phylum: Magnoliophyta
Class: Magnoliopsida
Subclass: Rosidae
Order: Fabales
Family: Fabaceae (Leguminosae)
Genus: Robinia

Other System Links

Plants: ROPS
Bayer: ROBPS
GRIN: 5238
ITIS: 504804
NPDN Pest: PCQBQBA
NPDN Host: 35030

Synonyms and Other Names

Other Common Names:
false acacia, yellow locust

Categories

Category: Hardwood Trees