Orbexilum onobrychis
{{Short description|Species of legume}}
{{speciesbox
|image = Orbexilum onobrychis.JPG
|status = G5
|status_system = TNC
|display_parents = 2
|genus = Orbexilum
|species = onobrychis
|synonyms = Psoralea onobrychis
}}
Orbexilum onobrychis, commonly called French-grass{{PLANTS|id=ORON|taxon=Orbexilum onobrychis|access-date=1 October 2018}} or lanceleaf scurfpea,{{cite web |url=http://www.herbarium.unc.edu/flora.htm |title= Flora of the Southern and Mid-Atlantic States |author= Alan Weakley |date= 2015}} 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.{{BONAP|ref|genus=Orbexilum|species=onobrychis|accessdate=30 September 2018}} Its natural habitat is primarily prairies and riverbanks, typically in mesic or wet areas.[http://www.illinoiswildflowers.info/prairie/plantx/french_grass.html French grass (Orbexilum onobrychis)] Illinois Wildflowers It is an uncommon species, and can be found in high-quality prairie remnants as well as more disturbed areas.{{cite book |last=Yatskievych |first=George |date=2013 |title=Flora of Missouri, Volume 3 |publisher=Missouri Botanical Garden Press |pages=113–114}}
It is a rhizomatous perennial that forms large colonies. It has pinnately trifoliate leaves, with large lanceolate leaflets. Its flowers are pale blue or purple, and produced in racemes. Bloom time is from late spring to early summer. 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.{{Cite web| publisher =NatureServe| title = Hystrichophora loricana| url = http://explorer.natureserve.org/servlet/NatureServe?searchName=Hystrichophora+loricana | access-date = 2018-10-01}}