A novel cyclopentenoid cyanogenic glycoside (1-(β-O-β-rhamnopyranosyl-β-D-glucopyranos cyclopent-2-en-1-nitrile 4-sulphate) has been isolated from Passipora coccinea. The structure was determined by means of the ¹H and ¹³C NMR spectrum of the sulphate and its corresponding acetate derivative. Identification of the sugar constituents was made by HPLC and TLC. Passicoccin is so far unique to subgenus Distephana and its presence here is evidence for a phylogenetic relationship between Distephana and subgenera Granadilla and Tacsonia.