Strophostyles leiosperma

Strophostyles leiosperma, known as slickseed fuzzybean, or smoothseed / small-flower wildbean[2][3] 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.[4][5] 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.

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[1]
Phaseolus leiospermus Torrey & A.Gray) Piper Phaseolus pauciflorus Benth. Strophostyles pauciflora S. Watson

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.[4] Likewise, the specific epithet leiosperma means "smooth seed."[6] It is also the most likely of these species to be capable of self-fertilization.[4]

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  S. leiosperma flower & unripe pod