A flavus and A. umbratus forage little if at all on the surface of ground but instead have subterranean territories tending to concentrate around the roots of certain plants. By digging most (14) of the Cnicus lanceolatus; all (36) Rumex crispus; 65 large samples of the principal clumps of Carduus tenuiflorus; 21 Senecio jacobea; and 3 samples of open turf on 0.2 acre at South Haven Peninsula, Dorset, England, the mixed population of ant species was found concentrated in the following respective percentages of the plant samples: 75, 64, 26, 21 and 6.