Robinia hispida

This introduced shrub is 3-10' tall and across, branching abundantly. The bark of the trunk and larger branches is gray and fairly smooth. Young branches are green, terete, and very bristly-hairy. These long bristly hairs are purple-brown and sticky from minute glands. Alternate compound leaves occur at intervals along young branches; they are ¾–1½' long and odd-pinnate with 7-15 leaflets. The green rachis (central stalk) of each odd-pinnate leaf is slightly sticky-hairy. At the base of each rachis is a pair of sharp spines. Individual leaflets are 1-2" long and one-half as much across; they are broadly oblong, smooth along their margins, and hairless (or nearly so). Their upper surfaces are medium green, while their lower surfaces are pale green. Both axillary and terminal racemes of flowers are produced. Each raceme has 5-15 rosy-pink flowers; both the central peduncle of the raceme and its pedicels are covered with purple-brown bristly hairs. Each flower is about 1" long and nearly as wide; it has a short tubular calyx and 5 petals. The calyx is covered with purple-brown bristly hairs and it has 5 teeth. The petals are arranged like a typical pea-flower

The most striking aspect of this shrub consists of the bristly purple-brown hairs that cover young stems, pedicels, calyces, and seedpods. These hairs probably discourage herbivory by some insects and deter nectar-robbing of the flowers by ants. Another species in this genus with a similar appearance is Robinia viscosa (Clammy Locust). While stems, calyces, seedpods, etc. of this shrub are covered by short sticky glands, they lack the long purple-brown hairs of Bristly Locust. Another species, Robinia pseudoacacia (Black Locust), is a tree that has spread northward into all areas of Illinois. This tree also lacks the long purple-brown hairs of Bristly Locust and its flowers are white, rather than rosy pink. In its native range in southeastern United States, Bristly Locust is a rather variable shrub and different varieties have been described. The typical variety (var. hispida) has been described here because it is more often encountered than other varieties of this shrub.

hispida: rough with stiff hairs (hispid)

Bristly Locust has escaped from cultivation and has naturalized in different areas of Illinois (see Distribution Map). It is native to the hilly regions of southeastern United States, but will adapt to areas that are north of its original range. Habitats include thin upland woodlands, woodland edges, thickets, fence rows, roadside embankments, banks of drainage canals, vacant lots, and overgrown waste areas. Because of its attractive flowers and foliage, Bristly Locust is often cultivated as an ornamental shrub. Sometimes it is planted along embankments to control erosion.

Agati grandiflora (L.) Desv.:
United States (North America)
Caribbean (Caribbean)

Note: This information is based on publications available through Tropicos and may not represent the entire distribution. Tropicos does not categorize distributions as native or non-native.

Robinia hispida L.:
Canada (North America)
United States (North America)
China (Asia)

Note: This information is based on publications available through Tropicos and may not represent the entire distribution. Tropicos does not categorize distributions as native or non-native.

Robinia grandiflora L.:
India (Asia)

Note: This information is based on publications available through Tropicos and may not represent the entire distribution. Tropicos does not categorize distributions as native or non-native.

Robinia speciosa Ashe:
United States (North America)

Note: This information is based on publications available through Tropicos and may not represent the entire distribution. Tropicos does not categorize distributions as native or non-native.

Robinia grandiflora Ashe:
United States (North America)

Note: This information is based on publications available through Tropicos and may not represent the entire distribution. Tropicos does not categorize distributions as native or non-native.

Canada

Origin: Exotic

Regularity: Regularly occurring

Currently: Unknown/Undetermined

Confidence: Confident

United States

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

Perennial, Shrubs, Woody throughout, Stems woody below, or from woody crown or caudex, Plants with rhizomes or suckers, Nodules present, Stems erect or ascending, Stems less than 1 m tall, Stems 1-2 m tall, Plants gland-dotted or with gland-tipped hairs, Stems solid, Stems or young twigs sparsely to densely hairy, Leaves alternate, Leaves petiolate, Stipules conspicuous, Stipules setiform, subulate or acicular, Stipules deciduous, Stipules free, Leaves compound, Leaves odd pinnate, Leaf or leaflet margins entire, Leaflets opposite, Stipels present at base of leaflets, Leaflets 5-9, Leaflets 10-many, Leaves glandular punctate or gland-dotted, Leaves hairy on one or both surfaces, Inflorescences racemes, Inflorescence axillary, Inflorescence or flowers lax, declined or pendulous, Flowers zygomorphic, Calyx 2-lipped or 2-lobed, Calyx hairy, Petals separate, Corolla papilionaceous, Petals pinkish to rose, Banner petal suborbicular, broadly rounded, Wing petals narrow, oblanceolate to oblong, Wing tips obtuse or rounded, Keel tips obtuse or rounded, not beaked, Stamens 9-10, Stamens diadelphous, 9 united, 1 free, Filaments glabrous, Style terete, Style hairy, Style hairy on one side only, Fruit a legume, Fruit stipitate, Fruit unilocular, Fruit freely dehiscent, Fruit elongate, straight, Fruit exserted from calyx, Fruit hairy, Fruit 3-10 seeded, Seeds reniform, Seed surface smooth, Seeds olive, brown, or black.

Bristly Locust has escaped from cultivation and has naturalized in different areas of Illinois (see Distribution Map). It is native to the hilly regions of southeastern United States, but will adapt to areas that are north of its original range. Habitats include thin upland woodlands, woodland edges, thickets, fence rows, roadside embankments, banks of drainage canals, vacant lots, and overgrown waste areas. Because of its attractive flowers and foliage, Bristly Locust is often cultivated as an ornamental shrub. Sometimes it is planted along embankments to control erosion.

The nectar of the flowers attracts honeybees, bumblebees, and other long-tongued bees; occasional butterflies (which are poor pollinators), and possibly the Ruby-Throated Hummingbird. Miscellaneous insects feed on Robinia spp. in general or Robinia hispida (Bristly Locust) in particular, including the caterpillars of skippers and moths, stink bugs, leaf beetles, the larvae of long-horned beetles, and thrips (see Insect Table for a listing of these species). Birds and mammals apparently make little use of Robinia spp. as sources of food, although Bristly Locust may provide protective cover and habitat for bird nests. Photographic Location

In Great Britain and/or Ireland:
Fungus / parasite
Microsphaera pseudacaciae parasitises Robinia hispida

The following is a representative barcode sequence, the centroid of all available sequences for this species.

Barcode of Life Data Systems (BOLDS) Stats
Public Records: 1
Specimens with Barcodes: 4
Species With Barcodes: 1

Rounded Global Status Rank: G4 - Apparently Secure

Canada

Rounded National Status Rank: NNA - Not Applicable

United States

Rounded National Status Rank: N4 - Apparently Secure