Review and remarks on current generic delimitations in the myxomycetes, with special emphasis on Licea, Listerella and Perichaena
Eliasson, Uno H.
Genera and species of myxomycetes have been based traditionally on morphological features of the fruitbodies (sporocarps). Certain species bridge the gap between two genera by combining morphological characters, such as is the case for Hemitrichia leiocarpa, which combines characters of Hemitrichia and Arcyria and could equally well be placed in either genus on morphological grounds. A few species of Physarum and Badhamia combine characters of both genera. Molecular investigations are today a powerful tool for investigating evolutionary relationships, and there is molecular evidence that the two physaraceous genera mentioned above can no longer be maintained as presently circumscribed. Paraphyly has been demonstrated in the Stemonitales and additional molecular data are likely to necessitate changes in the circumscription of some genera. Certain species of Licea and Perichaena have minute sporocarps with simple morphology. Smaller sporocarps of some species of Perichaena may lack a capillitium and be morphologically similar to species of Licea, which blurs the line of separation between these two genera. The genus Licea remains enigmatic and is almost certainly unnatural, even after the removal of L. fimicola to a separate genus. Additional molecular investigations are necessary to elucidate the relationships among the different species.