Family: Lamiaceae

Origin, Description & Uses:
Mesosphaerum pectinatum, commonly known as comb hyptis, is a tropical herbaceous plant native to parts of the Americas, including Central and South America. It is a fast-growing, aromatic plant that typically thrives in warm, open environments such as pastures, roadsides, and disturbed areas. Comb hyptis produces small purple to lavender flowers arranged in dense clusters and has hairy stems and leaves that emit a strong scent when crushed. In some regions, it has been used in traditional herbal remedies and as a minor forage plant, though it is not widely cultivated for ornamental or agricultural purposes.

Risks & Threats:
Comb hyptis is naturalized across the Hawaiian Islands, including Kauaʻi, Oʻahu, Molokaʻi, Lānaʻi, Maui, and Hawaiʻi. It possesses traits that raise concern, such as rapid growth, prolific seed production, and the ability to thrive in disturbed habitats, allowing it to spread aggressively. This species can form dense stands that outcompete native vegetation and desirable pasture species, potentially altering ecosystem structure and reducing biodiversity. Its persistence and adaptability make it difficult to manage once established. Because it is naturalized and could detrimentally impact tropical island ecosystems, it is recommended to avoid intentional cultivation and instead choose low-risk or native plant alternatives.

High Risk Traits:

• Elevation range exceeds 1000 m, demonstrating environmental versatility
  
• Thrives in tropical climates
  
• Possibly naturalizing on Oahu, Hawaiian Islands (confirmation needed)
  
• Latex highly caustic to the skin, possibly poisonous if ingested
  
• Tolerates many soil types
  
• Seeds dispersed by birds and intentionally by people
  
• Seeds able to be stored for extended periods; May form a persistent seed bank
  
• Able to coppice and resprout after cutting

Low Risk Traits:

• No reports of invasiveness or naturalization (with the possible exception of Oahu(), but no evidence of widespread introduction outside native range
  
• Unarmed (no spines, thorns or burrs)
  
• Provides fodder for livestock (palatable despite reports of toxicity)
  
• Ornamental
  
• Not reported to spread vegetatively
  
• Limited ecological information makes accurate risk prediction difficult