DE LUNA, EFRAIN1* and BEATRIZ BIASUSO2. 1Sistematica Vegetal, Instituto de Ecologia, Xalapa, Ver, Mexico.; 2Fundacion M. Lillo, Fac. C. Naturales, UNT, San Miguel de Tucuman, Argentina. - Morphometric variation and species delimitation in the Braunia exserta complex (Hedwigiaceae).
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