Acacia tortilis, A. karrooandDichrostachys cinereasubsp.africanatrees were divided into nine height classes, with increments of 0.5 m. The abundance ofP. maximumgrowing under their canopies was estimated by scoring on a scale of 0 (noP. maximum)to 3 (P. maximumpredominates). Presence ofP. maximumwas mainly associated with larger trees of all three species, and ranged from virtual absence under small trees to pure stands under larger trees. Spearman's rank correlations between tree height and the abundance ofP. maximum(median score) were positive and significant.Panicum maximumattained pure stands (score 3) under smallerA. tortilistrees than under eitherA. karrooorD. cinerea. A median score of 3 was attained underA. tortilis, A. karrooandD. cinereatrees of >2.0 m, >4.0 m and >4.5 m, respectively. Tree height therefore represents a simple index of conditions favourable toP. maximum.