To supplement current thin-layer chromatographic methods for separation and quantitation of plant phospholipids, an alternative method, high-performance liquid chromatography was developed. The major inositol-containing lipids from the pulvini of Samanea saman Merr. were identified as phosphatidylinositol, phosphatidylinositol phosphate, and phosphatidylinositol bisphosphate based on comigration with authentic standards on high-performance liquid chromatography and on thin-layer chromatography. The patterns of incorporation of radioactivity into the putative phosphatidylinositol and phosphatidylinositol phosphate were consistent with these identifications when pulvini were labeled with [(3)H]glycerol, [(3)H]inositol, or [(32)P]orthophosphate. Analysis of the products of enzymic hydrolysis, of chemical deacylation, and of ;fingerprint' methanolysis of these phospholipids confirmed the identifications.