A novel cyclopentenoid cyanogenic glycoside, passisuberosin (1-(B-Dglucopyranosyloxy)4hydroxy-2,3 epoxycyclopentanenitrile), has been isolated from Pussigora suberosa Its structure was determined by means of 'H NMR and "C NMR and the identity of the glycosidic moieties by HPLC and TLC. A probable C-l epimer, epipassisuberosin, was also present, as were smaller amounts of passicoriacin and epipassicoriacin, previously isolated from Possijora coriacea. In addition, the presence of diglucosides of pas&t&rosin and epipassisuberosin was detected. These compounds differ in structure from those producad by other members of section Cieca, subgenus PIectostemma of Pawflora; the data suggest that the taxonomic placement of these two species should be reevaluated.