Family: Pteridaceae

Origin, Description & Uses
Pteris vittata (Chinese brake, ladder brake) is a fern native to the Tropical and Subtropical Old World extending into the southwestern Pacific. It is a hardy, fast-growing fern commonly found in warm, humid environments such as rocky slopes, walls, roadsides, and disturbed forest edges. The plant produces distinctive arching fronds with finely divided leaflets, giving it a lacy appearance. It is sometimes grown as an ornamental fern and is also widely known for its ability to accumulate arsenic from soils, making it useful in research and applications related to phytoremediation and environmental cleanup.

Risks & Threats
This species is naturalized throughout the Hawaiian Islands (Kauaʻi, Oʻahu, Molokaʻi, Lānaʻi, Maui, and Hawaiʻi) and possesses traits that are cause for concern, including rapid growth, tolerance of poor soils, and strong colonization ability in disturbed habitats. Pteris vittata can spread into rocky crevices, walls, and open areas where it may compete with or displace native vegetation, particularly in sensitive lowland and urban-edge ecosystems. Because it is already widespread, continued planting or spread can still contribute to local ecological pressure and further expansion into less disturbed habitats. It is recommended to choose low-risk or native alternatives when available, and to avoid planting or spreading this species in areas where it is not yet dominant to help minimize further impacts on Hawaiʻi’s tropical island ecosystems.

High Risk Traits:

• Elevation range exceeds 1000 m, demonstrating environmental versatility
  
• Thrives in tropical climates
  
• Widely naturalized in the Hawaiian Islands and elsewhere
  
• Weedy fern of disturbed habitats
  
• Potential environmental weed
  
• Other Pteris species have become invasive
  
• Accumulates arsenic from soil, becoming toxic
  
• Spores a possible human allergen
  
• Tolerates many soil types
  
• Produces viable spores that are dispersed by wind, water and probably externally by humans and animals
  
• Hybridizes with other Pteris species
  
• Can reproduce asexually by agamospermy and vegetatively by rhizomes
  
• Prolific spore production

Low Risk Traits:

• Unarmed (no spines, thorns or burrs)
  
• Palatable to animals despite potential toxicity
  
• Ornamental
  
• Spores may be short-lived in the soil and are unlikely to form a persistent spore bank