Abstract Populations of Taraxacum, dandelion, on a Northumberland sand dune system contain 27 agamospecies. Demographic parameters for subpopulations containing a preponderance of two closely related agamospecies, Taraxacum lacistophyllum and T. brachyglossum are described. High and low density populations were stable over a 3 year period. The estimated turnover times differed between densities and species. The early growth characteristics of the two species are described. The plastochrons of the two species are distinct, as are the growth patterns of the leaves, the total leaf length per plant, the number of leaves and rate of leaf birth, and the patterns of allocation of dry weight to the root, shoot, and reproductive organs of the plant. Differences between the species were observed in fruit, scape height, the wind speed required to achieve fruit dispersal, and the pattern of fruit dispersal at different wind speeds. The origin and maintenance of agamospecies diversity is discussed in relation to the observed life history variation.