Orbexilum onobrychis

Orbexilum onobrychis, commonly called French-grass[1] or lanceleaf scurfpea,[2] is a species of flowering plant in the legume family (Fabaceae). It is native to the eastern United States where its range is concentrated in the Midwest and Upper South.[3] Its natural habitat is primarily prairies and riverbanks, typically in mesic or wet areas.[2][4] It is an uncommon species, and can be found in high-quality prairie remnants as well as more disturbed areas.[4][5]

Orbexilum onobrychis
Conservation status
Secure  (NatureServe)
Scientific classification
Kingdom:	Plantae
Clade:	Tracheophytes
Clade:	Angiosperms
Clade:	Eudicots
Clade:	Rosids
Order:	Fabales
Family:	Fabaceae
Subfamily:	Faboideae
Tribe:	Psoraleeae
Genus:	Orbexilum
Species:	O. onobrychis
Binomial name
Orbexilum onobrychis (Nutt.) Rydb.
Synonyms
Psoralea onobrychis

It is a rhizomatous perennial that forms large colonies. It has pinnately trifoliate leaves, with large lanceolate leaflets.[5] Its flowers are pale blue or purple, and produced in racemes. Bloom time is from late spring to early summer.[4] Its fruits are beans, which are 6–8 mm long and distinctively warty.

The caterpillars of the rare moth Hystrichophora loricana are known to use Orbexilum onobrychis as their exclusive foodplant.[6]