The presence, in plants extracts, of factors capable of promoting cell division has been known for some time (Goldacre and Bottomley 1959; Miller 1961) and such compounds have been partially purified (Miller 1961; Zwar, Bottomley, and Kelford 1963). The germination of seeds normally involves cell division as well as cell enlarge-ment (Mayer and Poljakolf-Mayber 1963). Therefore it seemed of interest to investi-gate whether kinins occur in seeds or are formed during their germination. Lettuce seeds were used because their physiology has been studied extensively. We have also tried to partially characterize their kinins.