Family: Fabaceae

Origin, Description & Uses
Psophocarpus tetragonolobus, commonly known as winged bean, asparagus pea, four angle bean, Goa bean, or princess pea, is a tropical climbing legume believed to have originated as a cultivated plant from eastern tropical Africa. It produces distinctive four-winged pods, lush green vines, and attractive blue to purple flowers. Nearly all parts of the plant are edible, including the pods, leaves, flowers, seeds, and tubers. Winged bean is widely grown in tropical regions as a nutritious food crop and is valued for its high protein content, nitrogen-fixing ability, and usefulness in home gardens and small-scale agriculture.

Risks & Threats
Winged bean is considered a low risk species for Hawaii. While it is a vigorous tropical vine, it is primarily dependent on cultivation and is not known to spread aggressively or invade natural ecosystems in the Hawaiian Islands. The species has not demonstrated significant invasive tendencies in tropical island environments, and its risks to native habitats appear minimal when properly managed. As with many fast-growing legumes, gardeners should monitor growth to prevent unwanted spreading into nearby vegetation, but overall this species is regarded as a useful and relatively low-risk crop plant.

High Risk Traits:

• Elevation range exceeds 2000 m in tropical latitudes, demonstrating environmental versatility
  
• Thrives in tropical climates
  
• Reportedly naturalized (or persisting from cultivation) in Brazil, New Zealand and possibly elsewhere (but no evidence in the Hawaiian Islands to date)
  
• Possibly allelopathic
  
• Raw seeds may be toxic
  
• Tolerates many soil types
  
• Climbing and potentially smothering growth habit
  
• Tuberous roots (may allow plants to persist and regrow after damage or removal of above-ground vegetation)
  
• Reproduces by seeds
  
• Self-fertile
  
• Perennial, but able to reach maturity in <1 growing season
  
• Seeds dispersed by people
  
• Seeds hard coated and able to be stored for several years; likely to form a persistent seed bank

Low Risk Traits:

• A domesticated plant known only from cultivation
  
• No evidence of negative impacts due to cultivation
  
• Unarmed (no spines, thorns, or burrs)
  
• Provides fodder for livestock
  
• Require full sunlight (could limit ability to spread into intact forests)
  
• Edible to humans
  
• Not reported to spread vegetatively
  
• Relatively large pods and seeds unlikely to be inadvertently dispersed