Family: Asteraceae

Origin, Description & Uses
Wollastonia biflora is a low-growing, sprawling coastal shrub with a remarkably broad native range extending from the western Indian Ocean and the east coast of Africa through tropical Asia to the Pacific Islands, including many parts of Oceania. It is well adapted to harsh seaside environments, where it grows on beaches, coastal dunes, and rocky shorelines exposed to salt spray and strong winds. The plant has fleshy green leaves and bright yellow, daisy-like flowers that attract pollinating insects. Because of its tolerance of salt, drought, and poor soils, it is occasionally planted for coastal landscaping, dune stabilization, and erosion control. In some Pacific cultures, it has also been used in traditional medicine and as a source of plant materials for local uses.

Risks & Threats
Wollastonia biflora is considered a low-risk species for Hawaii. Although it spreads by seed and can also root from stem fragments, it is primarily associated with naturally disturbed coastal habitats and has not demonstrated aggressive invasive behavior outside its native range. Its growth is generally limited to exposed shoreline environments rather than intact native forests or upland ecosystems. While it should be monitored when planted near sensitive coastal habitats, current evidence indicates that Wollastonia biflora poses little risk of becoming a widespread environmental weed in Hawaii and is unlikely to significantly impact native ecosystems under normal conditions.

High Risk Traits:

• Weedy in native Pacific range (coastal plantations, ruderal sites)
  
• Sprawling/climbing habit can smother undergrowth
  
• Tolerates rocky volcanic and limestone substrates
  
• Vegetative spread via rooting at nodes
  
• Intentionally spread by humans for medicinal use
  
• Seeds dispersed by seawater (buoyant achenes)
  
• Produces viable seed

Low Risk Traits:

• Not naturalized beyond native range
  
• Not an environmental weed
  
• No allelopathy, parasitism, or spines
  
• Palatable to livestock
  
• Non-toxic to humans (used as food/medicine)
  
• Not shade-tolerant
  
• Not dispersed by wind, birds, or external animal attachment