Family: Xyridaceae

Origin, Description & Uses:
Xyris complanata, commonly known as yellow-eyed grass, is a grass-like perennial native to southern China, Hainan, tropical Asia, and northern to eastern Australia. It typically grows in wet habitats such as marshes, swamps, stream margins, and seasonally flooded areas. The plant forms dense clumps of flattened, sword-like leaves and produces slender flowering stalks topped with distinctive cone-shaped flower heads that bear small, bright yellow flowers. Although it is not widely cultivated as an ornamental, it may be grown in water gardens or naturalistic wetland plantings and has been used in parts of its native range for traditional medicinal purposes.

Risks & Threats:
Xyris complanata is naturalized in Hawaiʻi, including on Kauaʻi and Hawaiʻi Island, and possesses traits that are cause for concern. It is well adapted to wet environments, produces abundant seed, and can establish persistent populations in wetlands, marshes, and other moist habitats. Dense stands may compete with native wetland vegetation and alter the structure and function of sensitive ecosystems. Because this species has the potential to detrimentally impact tropical island ecosystems, planting and intentional spread are not recommended. When suitable, choose a low-risk or native alternative instead. Where Xyris complanata is already widespread, efforts should focus on managing existing populations and preventing its use or spread into areas where it is not yet widely established to help minimize further ecological impacts.

High Risk Traits:

• Elevation range exceeds 1000 m, demonstrating environmental versatility
  
• Thrives in tropical climates
  
• Naturalized on Kauai and Hawaii islands (Hawaiian Islands)
  
• Identified as a threat to native vegetation in montane wet ecosystems
  
• Other Xyris species are invasive weeds
  
• Tolerates many soil types
  
• Reproduces by seeds
  
• Reaches maturity rapidly
  
• Seeds dispersed by water, intentionally by people and possibly by other vectors
  
• Prolific seed production (1000s of seeds)
  
• Forms a persistent seed bank

Low Risk Traits:

• Unarmed (no spines, thorns, or burrs)
  
• Non-toxic
  
• Ornamental
  
• Not reported to spread vegetatively