A data set consisting of 14 Evolutionary Units (EU), diploid Avena spp. [A. hispanica, A. brevis, A. canariensis, A. clauda, A. damascena, A. eriantha, A. matritensis, A. lusitanica, A. hirtula, A. longiglumis, A. nuda, A. strigosa, A. ventricosa and A. wiestii] was used to compare the results obtained by 2 numerical cladistic methods. Cladograms were obtained from Farris'' method of computing Wagner trees and from Estabrook''s compatibility and cliques approach. Only a few cladograms from each method are similar. It is maintained that in any cladistic study a number of different analyses should be made, using various methods, so that the most plausible cladogram can be selected. The choice is subjective to a degree, and the need for optimality criteria for making that choice is stressed.