Family: Fabaceae
Guilandina bonduc(syn. Caesalpinia bonduc), known as nickerbean, gray nickers, hihikolo, kākalaioa, or kinikini, is a pantropical shrub or scrambling vine found along coasts and inland dry areas across the tropics. In Hawaiʻi, it is considered either indigenous or an early Polynesian introduction and occurs in dry, mostly open, and often disturbed habitats from 15–230 m in elevation on Niʻihau, Kauaʻi, Oʻahu, Molokaʻi, East Maui, and Hawaiʻi Island. The plant forms thorny thickets, has yellow flowers, and produces smooth gray seeds that float long distances. These seeds are commonly used for lei making, have been powdered for traditional medicinal purposes, and are sometimes used by children as marbles.
While Guilandina bonduc has cultural and practical uses, it also has the potential to become weedy in some environments. Its floating seeds allow it to disperse easily, and its ability to form dense, spiny thickets can crowd out native coastal and dryland vegetation. In disturbed areas, it may spread rapidly and alter habitat structure. Careful managing and monitoring are recommended when this species grows near natural areas to prevent unwanted spread and protect native ecosystems.
High Risk Traits:
- Naturalized pantropically, in Hawai'i either indigenous or an early introduction
- Forms dense, spiny thickets
- Climbing/smothering growth habit
- Tolerates saline, acidic, alkaline, and flooded soils
- Reproduces vegetatively (layering, resprouting)
- Seeds dispersed intentionally (human use) and unintentionally (attachment)
- Water-dispersed (long-term floating viability)
- Persistent seed bank
- Congeneric species is weedy
Low Risk Traits:
- Not allelopathic or parasitic
- Low toxicity to animals/humans
- Not a major pest host
- Not shade tolerant
- Not a prolific seed producer
