In this second paper on the biosystematics of the Dutch halophilous Spergularia species, the results are reported of a study of the morphological variation of S. marina by means of population samples from all parts of the Dutch area. This study was supplemented by the rearing of plants from seed samples in the experimental garden. The seeds of S. marina are usually unwinged, but some plants also produce a few broadly winged seeds and in one population plants occur whose proximal capsules contain mainly broadly winged seeds. The differences between the populations persist in cultivation and are chiefly attributable to genetic differences. Winged seeds are upon the average larger and heavier than unwinged ones and also produce larger seedlings than the latter. The relative lengths of fruiting calyx and capsule do not provide a reliable diagnostic character in respect of S. media. The number of stamens per flower varies from 0 to 10 and there are great individual differences in numbers, but in certain plants the average number is always high and in other ones always low. These differences are partly caused by heriditary factors. The growth habit and some other vegetative characters vary too widely to be of appreciable taxonomic significance.