As a first step toward a phylogenetic analysis and classification of Braunia exserta species complex, character variation was studied in populations of B. exserta, B. reflexifolia and B. tucumanensis from Argentina, Bolivia, Chile and Peru. The goal of this study was to discover groups of populations that could be proposed as putative species. Specific questions addressed in this study were: 1) what is the extent of morphological variation in each of the three putative species in the complex?, 2) are there three phylogenetic distinct groups? Two approaches were employed to answer these questions. First, twelve populations (n=116) were studied for gametophyte and sporophyte quantitative characters. Multivariate analyses (ordination techniques and discriminant analyses) were used to describe morphologically homogeneous units. Second, character variation within and among twelve populations was evaluated with Analyses of Variance (ANOVA) followed by multiple comparison tests. Results of these tests were used to classify variation in character states, as basis for cladistic analyses. The morphological data matrix was complemented by additional qualitative characters from our examination of specimens and types. Cladistic analyses reconstructed three main lineages that correspond to the three morphometric groups detected in multivariate analyses. A taxonomic conclusion is that each of those groups should be given the rank of species: Braunia exserta, B. reflexifolia and B. tucumanensis.

Key words: Hedwigiaceae, phylogenetic species, quantitative characters