The diameters of fibres from phytobezoars varied between 2 and 30 microns, with an average 58% measuring less than < 15 microns, 36% between 15 and 23 microns, and 6% greater than 23 microns. These diameters were very similar to those of the pappus hairs surrounding the seeds of the Karoo bushes
In a series of in virtro experiments (n = 64) using the mature flowers or seeds and pappus hairs of Karoo bushes Chrysocoma ciliata, Dimorphotheca cuneata, Eriocephalus ericoides, Gazania krebsiana and Gnidia polycephala, small phytobezoars were formed from material of E. ericoides, G. krebsiana and