At 10−3M, isovitexin, a C-glycosylflavone isolated from leaves ofRhynchosia minima(Leguminosae), inhibits cell plate formation resulting in the production of binucleate and occasionally multinucleate cells. A 48-hour treatment caused nucleolar fission leading to multinucleolate condition. At 10−5M and 10−7M, isovitexin seldom induced any cytologic abberations, but promoted mitosis up to 48 hours from treatment and suppressed it thereafter. The potentialities of isovitexin render it useful in studies on cell cycle and as a cytokinin-like substance.