The Pattern of Distribution of Agrostis and Festuca Plants of Various Genotypes in a Sward

S ummary Samples from a population of plants present in a grazed hill sward were isolated and grown as spaced individuals at a lowland site. The predominant taxa present were Agrostis , chiefly A. tenuis Sibth., and Festuca rubra L. Within each species, there was considerable variation between plants obtained from a relatively small area of sward. From an examination of morphological characters and tests of self‐ and cross‐compatibility among plants, an indication of the number of genotypes present was obtained. Eighty‐four putative genotypes of Agrostis and forty of Festuca were identified. A map is given showing the position of each putative genotype in the original population and the structure of Agrostis‐Festuca swards is discussed.