This yellow-flowering native vine is found across most of the state, less so in the far northern counties. Butterfly enthusiasts plant this vine in their gardens. It is host to the Cassius Blue, Gray Hairstreak, and Long-Tailed Skipper butterflies. The flowers are edible raw or cooked, and taste alot like fresh green beans to me. They are cooked as a vegetable in both Ethiopia and Malawi. To be on the safe side, go easy on them, don't eat too many, as some species of plants with yellow flowers "tend to be laxative" or even emetic. Know that this species is a myrmecophyte, in other words, it has a symbiotic relationship with ants. More often than not, the flowers will be accompanied by one or more ants, so you may want to brush them off before consuming the flowers. Very young whole seedpods are eaten raw as a trailside nibble, although they tend to get stringy when they approach two inches long. This bean may be planted as a green manure as it "nodulates well in wet and slightly saline soils." It is supposedly "nonspecific in its Rhizobium requirement." It is also planted as a protein-rich forage and may perform well in both shady and wet locations. NOTE: Vigna species are actually beans, not peas. The related, common Cowpea of vegetable gardens is Vigna unguiculata subsp. unguiculata.
CAUTION: To be on the safe side, go easy on them, don't eat too many, as many species of plants with yellow flowers "tend to be laxative."
EDIBLE FLOWERS: The flowers are edible raw or cooked, and taste alot like fresh green beans. To be on the safe side, go easy on them, don't eat too many, as many yellow flowers "tend to be laxative."
FLOWERS AND ROOTS ARE EATEN IN AFRICA: "The flowers of Vigna luteola are eaten as a boiled vegetable in Ethiopia and Malawi. In Malawi the roots are dug up by children, peeled and chewed to extract a sweet juice. The tender cooked seeds are edible." 
EDIBLE YOUNG SEEDS AND SEEDPODS: The seeds may be boiled and eaten. Very young whole seedpods are eaten raw as a trailside nibble, although they tend to get stringy when they approach two inches long.
CHEMICAL CONSTITUENTS OF THE SEEDS: "High levels of the amino acid cystine are present in the seeds." 
HARVEST SEASON: It may flower year-round, with most blossoms appearing during the warmer months. Seedpods develop all year, with most appearing in the fall.
MEDICINAL LEAVES AND FLOWERS: "In Ethiopia the leaves and flowers are mixed with Hagenia abyssinica to treat ulcers and syphilis. In Argentina it is used to control cholesterol levels and is reported to have antimicrobial properties as well. It is also used to treat "ghost sickness", a supernatural ailment, in Polynesia. [1,6]
BUTTERFLY GARDENING: Planted in butterfly gardens.  "Larval host plant for Cassius Blue (Leptotes cassius), Gray Hairstreak (Strymon melinus), Long-Tailed Skipper (Urbanus proteus) and the recently established Dorantes Skipper (Urbanus dorantes) butterflies." 
LANDSCAPE USES: It "can be somewhat weedy, but [is] useful in coastal sites." 
HABITAT RESTORATION: "Primarily recommended for natural landscapes and habitat restorations." 
GREEN MANURE, FORAGE, ETC.: Tropical Forages writes the following, "Can be used as a short-term (±3 years) legume in pasture, or as a green manure or hey in cropland. Despite its performance in a range of environments and applications, V. luteola has not achieved wide acceptance by farmers. It is, however, one of the best legumes for wet conditions and one of the best pioneer plants in such situations. It forms a good ground cover in shaded situations, but its twining habit may present problems with young trees."  "Because it is palatable for livestock and grows and nodulates well in wet and slightly saline soils, Vigna luteola has been tested as a pasture plant and cover crop in a number of countries including Ghana, Zambia, Argentina, Cuba and Australia. However, disadvantages as a pasture crop are its rather short life cycle, susceptibility to frost and to insect pests, and troublesome seed production."  "The plant is palatable for livestock and grows well in friable and slightly saline soils, meaning it is used as a pasture plant and as a ground cover in many countries, such as Ghana, Zambia, and Australia. However, its short lifespan and vulnerability to insects and frost can make it ineffective."  "Vigna luteola is nonspecific in its Rhizobium requirement."  "With a crude protein content of 17.4% of dry matter at flowering Vigna luteola qualifies as an excellent fodder." 
ANIMAL FEED NUTRITION: "17% protein has been recorded at flowering." 
INSECTICIDAL PROPERTIES: "The flavonoids quercetin and isorhamnetin, isolated from the leaves, are thought to play a role in the resistance mechanism against aphids. The seeds contain high levels of antimetabolic factors (tannins, phytic acid, inhibitors of trypsin and cystatin) implied in the resistance to storage pests." 
NATIVE TO: Some authors list it as non-native to Florida, it is listed as "native" by most authorities including the University of South Florida and Regional Conservation. [2,4] Regional Conservation writes, "Southeastern United States west to Texas [north to Pennsylvania - 5] and south to the Monroe County Keys; West Indies, Mexico, Central America and South America. Rare in the Monroe County Keys."  ANDY'S NOTE: Here in Florida it grows across the state, yet is absent from a number of northern counties. It is also native to parts of Africa. Tropical Forages lists the following countries as its native range: "Africa: Cameroon, Congo, Democratic Republic of Congo (Zaire), Egypt, Equatorial Guinea, Gabon, Ghana, Liberia, Nigeria, Mozambique, South Africa, Tanzania, Uganda, Zambia. Asia: Indonesia, Japan, Malaysia, Philippines, Sri Lanka, Taiwan, Thailand, Vietnam. Australasia: Australia, Papua New Guinea." It lists the USA as a naturalized region. 
HABITAT: "Pinelands, coastal uplands and disturbed sites." 
CONSERVATION: IRC SOUTH FLORIDA STATUS: Secure. 
DESCRIPTION: A climbing or creeping/spreading/climbing/scrambling vine. [1,4] A short-lived perennial. 
- HEIGHT: 6 to 20'. [4,5]
- LEAVES: Alternate. Trifoliate. Leafklets are oval, "becoming acute at the apex." 
- FLOWERS: Yellow, 3/4" long, showy, in pairs. Very often accompanied by a protecting ant. The flowers "are made of one large standard petal, two lateral wing petals, and two lower keel petals." 
- FLOWERING SEASON: All year long. 
- FRUIT: "Hairy pod (legume) 2 to 2 1/2" long. All year."  1/4" wide.
- SEEDS: Maturing to black, numerous.
ETYMOLOGY: "The name Luteola is derived from the latin for "yellow", in reference to the plant's yellow flowers." [1,6] Green Deane writes, "The genus is named for Professor Dominico Vigna, a 17th century Italian botanist and director of the botanical garden in Pisa." 
- LIGHT: Full sun. 
- SOIL: "Moist [1,4], well-drained sandy or limestone soils, with or without humusy top layer." 
- NUTRITIONAL REQUIREMENTS: "Low to moderate; it can grow in nutrient poor soils or soils with some organic content." 
- DROUGHT TOLERANCE: High; it does not require any supplemental water once established. 
- SALT WATER TOLERANCE: "Low; does not tolerate long-term flooding by salt or brackish water." 
- PROPAGATION: It "can be grown from seed. Sprinkle seeds on surface of soil and barely cover. Place container in full sun." 
RELATED SPECIES: The common Cowpea of vegetable gardens is Vigna unguiculata. It is vouchered as growing wild in eight Florida counties across Florida. 
Pond and River Margins, Coastal
Rate of GrowthFast
Sources for acquiring
It is cultivated by native plant and butterfly enthusiasts according to Regional Conservation. 
 Atlas of Florida Plants
 Florida Ethnobotany
 Regional Conservation
 Central Florida Wildflowers: A Field Guide to Wildflowers of the Lake Wales Ridge, Ocala National Forest, Disney Wilderness Preserve, and More than 60 State Parks and Preserves, Roger L. Hammer (2016)
 PROTA4U, Plant Resources of Tropical Africa
 International Association of Research Scholars and Fellows Symposium (1998)