Diversity and evolution of stem structure in Eleocharis (Cyperaceae)

Abstract Eleocharis (Cyperaceae) includes more than 300 species of perennial or annual herbs, frequently found on poorly drained soils. The are morphologicaly similar, and the taxonomy is difficult because their vegetative reproductive structures very reduced. Previous study stem architecture in subgenus Limnochloa showed that anatomical features help interpretation evolution, ecological aspects group. Our objectives were to add new characters from (= culm) structure, explore a greater number species, representatives other subgenera, these data phylogenetic analysis with molecular data. covered 68 obtained herbaria fixed material. In addition architecture, internal organization tissues, cross-section format, presence absence stretched cells aerenchyma air gaps plant size included morphological analysis. confirm spongy pattern ancestral condition while mixed septate patterns occurred independent punctually. Only format was variable among specimens uniform relevant for taxonomic use.