The populations of the seaward intertidal ends of the 1955 lava flows in Hawaii were studied during the first few years of their development. Different seral phenomena were recognized such as pioneer colonization, succession, disclimax, and subclimax. The term climax is used as a practical term to denote existence of an equilibrium between the populations and the environment. Appearance of the climax situation seems to be related to stability of the substratum for a period at least as long as six to ten years, but even populations on surfaces as old as 100 years are different from some that are on adjacent prehistoric surfaces.