A pea inhibitor was isolated as natural free acid and as its methyl ester from the garden peas (Pisum sativum L.) and they were identified with (+)-abscisic acid (Ia) and its methyl ester (Ib), respectively. On the other hand, sayanedine, mp 165-166°, C₁₇H₁₄O₅, which is a new isoflavone and which had kinetin-like activity in the tabacco pith callus bioassay, was also isolated from the same plant, and its chemical structure was confirmed to be 4'-hydroxy-7, 3'-dimethoxyisoflavone (VI) on the basis of spectral and synthetic evidences.