Family: Fabaceae

Senna macranthera (large-flowered cassia, caboclo) is a tree in the Fabacea family that grows 6 – 9 meters tall. It is native to Central and South America. Several species of Senna are well known for their therapeutic properties, being used in folk medicine to treat throat inflammation and constipation, so this plant is also known for having medicinal uses. It is reported to be naturalized in Guyana and Argentina but is not documented to be naturalized on any Hawaiian Islands to date. Caboclo is adapted to tropical climates, tolerates many soil types, is self-fertile, and has a fast growth rate. Its seeds are dispersed by many different means, including self-dispersal, by mammals (internally), by ants (externally), potentially by water and through intentional cultivation. Additionally, seeds may form a persistent seed bank. All these factors make it a high-risk plant for naturalization in Hawaiʻi.

High Risk Traits:

• Adapted to tropical climates
  
• Broad climate suitability and elevation range
  
• Naturalized in Argentina (but no evidence in the Hawaiian Islands to date)
  
• A pioneer tree that could establish in open, disturbed habitats
  
• Other Senna species are invasive weeds
  
• Shade tolerant
  
• Tolerates many soil types
  
• Reproduces by seeds
  
• Self-fertile (autogamous)
  
• Fast growth rate (but time to maturity unknown)
  
• Seeds dispersed by autochory (self-dispersal), by mammals (internally), by ants (externally), potentially by water and through intentional cultivation
  
• Seeds may form a persistent seed bank

Low Risk Traits:

• Despite naturalization, negative impacts have not been reported to date
  
• Unarmed (no spines, thorns, or burrs)
  
• Non-toxic
  
• Grows best in high light environments (dense shade may inhibit spread)