A phylogenetic analysis of the tribe Triticeae (Poaceae) based on morphological characters of the genera

Abstract

A phylogenetic analysis of Triticeae was performed by means of numerical methods. Five methods, each based on extreme assumptions of parameters so interpreted under Felsenstein's (1979) evolutionary model, were used: Camin–Sokal parsimony, Wagner parsimony, Dollo parsimony, polymorphism parsimony, and character-compatibility analysis. Although a considerable amount of parallelism was, for some time, suspected to have occurred in Triticeae (by Stebbins for instance) so that for this reason perhaps the assumptions of polymorphism parsimony might be most suitable for phylogenetic analysis, the five methods were used because the evolutionary assumptions for each investigated character are, and probably will long remain, unknown.Data input consisted of sets of hypothesized transformation series, each set subjected to analyses using the five methods. Results of an analysis provided the basis for altering the set of hypothesized transformation series for subsequent analysis. Analyses were carried out repeatedly until stabilization; that is until, in the author's judgment, the most parsimonious solution was arrived at and further trials were of diminishing return. The most parsimonious tree obtained served as a base for subsequent elaboration of the final tree, taking into consideration genetic information primarily, and for the erection of the proposed phylogenetic classification of Triticeae. A key is provided for identification of the groupings in the tribe. The proposed classification is discussed in the light of previous classifications, even though none of them were phylogenetic in the sense of Hennig.