''Phaseolus polystachios'', also known as the thicket bean or wild kidney bean, is a

perennial A perennial plant or simply perennial is a plant that lives more than two years. The term ('' per-'' + '' -ennial'', "through the years") is often used to differentiate a plant from shorter-lived annuals and biennials. The term is also wide ...

, herbaceous vine that is native to

North America North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Car ...

. It is unique among the ''

Phaseolus ''Phaseolus'' (bean, wild bean) is a genus of herbaceous to woody annual and perennial vines in the family Fabaceae containing about 70 plant species, all native to the Americas, primarily Mesoamerica. It is one of the most economically importan ...

'' in that its native range extends across the eastern temperate United States to southeast Canada, while most ''

'' are tropical or subtropical. It is the namesake for the Polystachios group clade, which is the most species-rich within ''Phaseolus'' (17 species). In spite of its common name, it is more closely related to the lima bean ('' Phaseolus lunatus''), and it holds potential as a crop wild relative due to its resistance to white mold ('' Sclerotinia sclerotiorum'').

Subordinate taxa

Subordinate taxa include ''Phaseolus polystachios'' var. ''polystachios,'' ''Phaseolus polystachios'' var. ''sinuatus,'' and ''Phaseolus polystachios'' var. ''smilacifolius''. The ''Phaseolus polystachios'' var. ''polystachios'' variety is listed as a special concern species and believed extirpated in

Connecticut Connecticut () is the southernmost state in the New England region of the Northeastern United States. It is bordered by Rhode Island to the east, Massachusetts to the north, New York to the west, and Long Island Sound to the south. Its cap ...

."Connecticut's Endangered, Threatened and Special Concern Species 2015"
State of Connecticut Department of Energy and Environmental Protection Bureau of Natural Resources. Retrieved 2 January 2017. (Note: This list is newer than the one used by plants.usda.gov and is more up-to-date.)

Ethnobotany and uses

''Phaseolus polystachios'' has been found in a few Native American archaeological sites in Oklahoma and Arkansas, with some evidence of artificial selection for indehiscent (non-shattering) pods. Its fruit and seeds can reportedly be eaten in much the same way as cultivated ''Phaseolus,'' although they are smaller.

Life history

''Phaseolus polystachios'' exhibits

hypogeal germination Hypogeal germination (from Ancient Greek [] 'below ground', from [] 'below' and [] 'earth, ground') is a botanical term indicating that the germination of a plant takes place below the ground. An example of a plant with hypogeal germination is t ...

and is

photoperiod Photoperiodism is the physiological reaction of organisms to the length of night or a dark period. It occurs in plants and animals. Plant photoperiodism can also be defined as the developmental responses of plants to the relative lengths of light a ...

sensitive, requiring day lengths greater than 10 hours to vine and flower. It overwinters via a tuberous root system.

Ecology

''Phaseolus polystachios'' inhabits well-drained soils and slopes, generally woodlands and thickets, and may form colonies. Their pods are eaten extensively by weevils.

References

polystachios Flora of North America {{Phaseoleae-stub