Dormancy and germination requirements, their variation throughout the year, and aspects of the seed population dynamics are studied in Melampyrum pratense L. (Rhinanthoideae), an annual hemiparasite. Germination occurs at low temperatures. Within this process a considerable period of epicotyl dormancy is involved. Dormancy preceding radicle germination may be present in varying degrees. In the field the germination response changes with time and appears to be related to macroclimatic changes, especially in temperature. Counts made on a small number of plots show that most seed losses occur on the forest floor during summer and autumn. Small mammals are the most likely and important cause accounting for these losses. The data on survival and germination, supplemented with information on seedlings and mature plants, allow the construction of a life table. It is also attempted to explain the coincidence in distribution which is often found between M. pratense and Deschampsia flexuosa. Data on the losses indicate that different pressures are exerted upon the seeds in various microhabitats by seed eating animals, leading to a spatial coincidence of M. pratense with sites with densely tufted grasses. Moreover, the possible ecological significance of the prolonged germination is discussed