Family: Menispermaceae

Origin, Description & Uses
Stephania japonica is native to Tropical and Subtropical Asia extending into the South Pacific. It is a twining, perennial vine in the moonseed family (Menispermaceae) that climbs over shrubs and trees using long, flexible stems. The plant produces distinctive round, shield-shaped (peltate) leaves and small clusters of flowers followed by berry-like fruits. It has been used in some regions as an ornamental vine and in traditional medicine, contributing to its spread through cultivation and human use.

Risks & Threats
Stephania japonica is potentially naturalized in Hawaiʻi (notably on Oʻahu) and possesses traits that are cause for concern, including vigorous climbing growth and the ability to smother surrounding vegetation. If it continues to spread, it could detrimentally impact tropical island ecosystems by overgrowing native understory plants, altering forest structure, and reducing habitat quality for native species. Because of these risks, choosing low-risk or native alternatives is strongly recommended when available. Where this species is already present, efforts should focus on managing existing populations and preventing further planting or spread into areas where it is not yet widely established, in order to minimize additional ecological impacts.

High Risk Traits:

• Elevation range exceeds 1000 m, demonstrating environmental versatility
  
• Thrives in tropical climates
  
• Naturalizing on Oahu, (Hawaiian Islands)
  
• A weed of tea plantations in Indonesia, Sri Lanka and North India/Nepal and of citrus crops
  
• Other Stephania species are invasive
  
• Roots reported to be toxic
  
• Shade-tolerant
  
• Reproduces by seeds and vegetatively by rooting at nodes or from stem fragments
  
• Seeds dispersed by birds, other frugivorous animals and intentionally by people
  
• Resprouts after flooding damage or fire

Low Risk Traits:

• Unarmed (no spines, thorns, or burrs)
  
• Leaves palatable to gibbons, deer and probably other browsing animals
  
• Dioecious (may limit ability to spread if only male or female plants are cultivated)