This species is endemic to Hawaii island and rare. The Hawaii Biodiversity and Mapping Program in 2008 reports the plant to have historically occurred in Kipahulu valley on Maui but is apparently extirpated from that island. USFWS reported in 2010 that only 24-26 wild plants exist in 10 populations. Unfortunately this species has not been listed as an endangered species and has remained on the 'Candidate' list since 1990. Elevation of this photo is around 4100ft/1250m.
Trailing vine growing on stabilized sands in back dunes habitat. A naturalized escape from cultivation found worldwide in tropical regions. Echinate fruit turns yellow with maturity and is edible.