Inmunological tests by Agar-diffusion (Oudin’s Method), have been applied to the serological relationships between some Argentine species belonging to the Prosopis genus of Mimosoideae. The comparison between the results obtained by gel-diffusion and other analogous tests by the precipitin technique and Photron- reflectometric evaluation, can support under a nonmorphological way the general arrangement of the Prosopis group by Burkart. Thus the proposed Algarobía section to which Prosopis caldenia, flexuosa, chilensis and alpataco belong can be easily identified by our serological tests, but a special position may be stressedfor the stricking morphologically aberrant P. sericantha. A section strombocarpa may be also supported by serological distances of P. strombulifera and P. torquata, moreover a section Monilicarpa for the P. argentina such as suggested by Ruiz Leal’s report, could be accepted in order to its serological relationships with the above mentioned species.
Our preliminary results point out again the general agreement between the physiological or analytical methods and the real assumptions of the morphological taxonomy.