Family: Cucurbitaceae

Origin, Description & Uses:
Cucumis metuliferus, commonly known as African horned cucumber or jelly melon, is a fast-growing annual vine native to sub-Saharan Africa. It belongs to the cucumber family (Cucurbitaceae) and is easily recognized by its bright orange, spiny fruit and lime-green, jelly-like interior. The plant produces sprawling vines with tendrils and yellow flowers, thriving in warm climates with full sun. African horned cucumber is cultivated primarily as a novelty or specialty fruit, used fresh in salads, desserts, beverages, and as an ornamental conversation piece in home gardens due to its unusual appearance and drought tolerance.

Risks & Threats:
Although Cucumis metuliferus is currently not known to be naturalized in Hawaiʻi, it does possess traits that are cause for concern. Its rapid growth, prolific seed production, tolerance of poor soils, and ability to spread along the ground could allow it to escape cultivation and establish in natural or disturbed areas. If introduced more widely, these traits could detrimentally impact tropical island ecosystems by competing with native vegetation and altering groundcover dynamics. To reduce the risk of unintended spread and protect Hawaiʻi’s unique environments, choosing a low-risk or native alternative is recommended.

High Risk Traits:

• Elevation range exceeds 1000 m, demonstrating environmental versatility
  
• Thrives in tropical climates
  
• Naturalized in Queensland, Australia, Venezuela, and possibly elsewhere
  
• A minor weed of disturbed areas and agriculture
  
• Other Cucumis species have become invasive
  
• Leaves have needly hairs and fruit with stout, broad-based, spiny protuberances
  
• Raw leaves may contain toxic compounds
  
• Tolerates many soil types
  
• Climbing plant may smother other vegetation
  
• Seeds dispersed by birds, frugivorous animals and intentionally by people
  
• Self-compatible
  
• Able to reach maturity in 8 weeks (annual)
  
• Orthodox seeds may form a persistent seed bank (longevity unknown)

Low Risk Traits:

• Fruit edible
  
• Seedless and spineless cultivars may reduce ability to spread or become a nuisance
  
• Requires full sun
  
• Not reported to spread vegetatively
  
• Herbicides may provide effective control