Strophostyles leiosperma

Strophostyles leiosperma
Typical flower & pod (Gray Summit, MO)
Scientific classification
Kingdom:	Plantae
Clade:	Tracheophytes
Clade:	Angiosperms
Clade:	Eudicots
Clade:	Rosids
Order:	Fabales
Family:	Fabaceae
Subfamily:	Faboideae
Genus:	Strophostyles
Species:	S. leiosperma
Binomial name
Strophostyles leiosperma (Torr. & A.Gray) Piper
Synonyms
Phaseolus leiospermus Torrey & A.Gray) Piper Phaseolus pauciflorus Benth. Strophostyles pauciflora S. Watson

Strophostyles leiosperma, known as slickseed fuzzybean, or smoothseed / small-flower wildbean is a species of herbaceous, vining legume native to the central to western U.S. It occurs west to Colorado and New Mexico, east to Louisiana, south to Mexico, and north to Minnesota. It is most easily distinguished from the other two Strophostyles species by the abundance of small silky hairs on its leaves and pods, and small pea-shaped flowers with a much reduced keel that is largely hidden by the wing petals.

This species is an annual to short-lived perennial. All parts tend to be smaller for S. leiosperma in general than its congeners, and it is a more diminutive plant overall. The leaflets are typically thin and rarely lobed (never deeply lobed). Unlike its congeners, its seeds rarely have a waxy, hairy covering, and it tends to occur in drier sites. Likewise, the specific epithet leiosperma means "smooth seed." It is also the most likely of these species to be capable of self-fertilization.

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  S. leiosperma flower & unripe pod