Family: Pteridaceae

Origin, Description & Uses
Pityrogramma austroamericana, commonly known as gold fern or gold-dust fern, is a tropical fern native to Central America and South America, ranging from Central America to Guyana and northern Argentina. This attractive fern is recognized for its delicate, finely divided fronds and the distinctive golden or yellow powdery coating found on the undersides of its leaves. It is sometimes grown as an ornamental plant for shaded gardens, landscaping, and naturalistic plantings because of its soft texture and striking foliage. In Hawaiʻi, this species has become naturalized on Niʻihau, Kauaʻi, Oʻahu, Molokaʻi, Lānaʻi, Kahoʻolawe, Maui, and Hawaiʻi Island, where it is commonly found in exposed dry areas, along roadsides and trails, on bare banks, and in disturbed open habitats from low elevations to over 1,500 meters.

Risks & Threats
Although visually appealing, Pityrogramma austroamericana is considered a high risk species in Hawaiʻi because it is naturalized and possesses traits associated with invasive behavior. The fern readily colonizes disturbed sites, spreads efficiently by spores, and can establish dense populations in open environments. Its ability to thrive in dry, exposed habitats allows it to compete with native vegetation and potentially alter plant communities in sensitive tropical island ecosystems. Because disturbed areas often serve as pathways for further spread into native habitats, this species may contribute to ecosystem degradation and reduced biodiversity over time. Due to these concerns, planting gold fern is discouraged, and choosing low risk or native alternatives is recommended for landscaping and restoration projects in Hawaiʻi.

High Risk Traits:

• Elevation range exceeds 1000 m, demonstrating environmental versatility
  
• Thrives in tropical climates
  
• Naturalized on all the main Hawaiian Islands and Australia
  
• Disturbance-adapted, and regarded as a weed, but var. austroamericana generally not mentioned as having detrimental impacts
  
• Possibly unpalatable (persists in areas heavily impacted by ungulates)
  
• Reproduces by spores
  
• Hybridizes with other Pityrogramma species and varieties
  
• Gametophytes are self-compatible
  
• Spores dispersed by wind, water, and along heavily trafficked areas
  
• Prolific spore production

Low Risk Traits:

• Despite naturalization, impacts unspecified or uncertain
  
• Unarmed (no spines, thorns, or burrs)
  
• Provides fodder for livestock (palatable despite reports of toxicity)
  
• Ornamental
  
• Persists in high light environments
  
• Not reported to spread vegetatively