Black Locust (also known as Yellow Locust, False Acacia)
Kingdom: Plantae, Division: Tracheophyta, Class: Magnoliopsida, Order: Fabales, Family: Fabaceae, Genus: Robinia, Species: Robinia pseudoacacia · Fabaceae (Legume, pea, or bean family) · Pinnately compound (deciduous)
Species
Robinia pseudoacacia
Leaf Type
Pinnately compound (deciduous)
Family
Fabaceae (Legume, pea, or bean family)
Shape
Elliptical to oval leaflets with rounded or slightly notched tips
Size
The entire compound leaf is roughly 8-14 inches long; individual leaflets are about 1-2 inches long, typical for mature specimens.
Margin
Entire (smooth margins)
Arrangement
Alternate on the stem, with leaflets arranged oppositely or sub-oppositely along the central rachis.
Rarity
Very Common
Color & Pattern
Rich medium to dark green on the upper surface, paler bluish-green underneath. No variegation or spots present.
Venation Pattern
Pinnate venation with a prominent central midrib and fine secondary veins branching out.
Texture & Surface
Smooth (glabrous) above with a matte to slightly satin finish, slightly paler and smoother beneath.
Description
Black Locust is a medium to large deciduous tree known for its deeply furrowed, dark bark, fragrant pendulous clusters of white pea-like flowers, and hard, durable timber. The compound leaves provide a delicate, fern-like canopy.
Key Features
Pinnately compound leaves with oval entire leaflets, paired spines at the nodes on twigs, and fragrant white hanging flower clusters.
Habitat
Found in open woods, disturbed areas, forest edges, and along roadsides. Prefers moist, rich soils and full sun, but highly adaptable to poor soils.
Geographic Range
Native to the eastern United States, primarily the Appalachian and Ozark regions, but widely naturalized across North America, Europe, and Asia.
Condition Notes
Good overall condition with minor insect feeding damage and edge tearing on a few lower leaflets, typical for wild-collected foliage.
Interesting Facts
Black Locust wood is exceptionally rot-resistant and hard, making it a favorite for fence posts, shipbuilding, and outdoor furniture without needing chemical treatments.
Medicinal & Uses
Used extensively for durable timber, erosion control, and honey production from its nectar-rich flowers. Bark and roots contain toxic compounds and have historical uses in herbal medicine with extreme caution.
Ecological Role
As a member of the Fabaceae family, it fixes nitrogen in the soil. It provides vital nectar for pollinators and cover for wildlife, though it can behave aggressively outside its native range.
Similar Species
Honey Locust (Gleditsia triacanthos), which features once- or twice-compound leaves and large branched thorns, and Wisteria, which has twining vines rather than upright tree growth.
Foraging Tips
Look for trees with deeply grooved bark, paired stipular spines, and hanging clusters of legume pods in winter. Flowers are edible when properly identified, but other parts are toxic.
Toxicity Warning
Moderately Toxic. The bark, roots, leaves, and seeds contain toxins (such as robin and phasin) that can cause severe digestive upset, weakness, and poisoning if ingested by humans or livestock.