Leaf venation of the Lauraceae of the Distrito Federal, Brazil, and new proposed venation patterns

Leaves of 18 species of Lauraceae that grow in the Distrito Federal (Brazil) were studied with the goal of characterizing their venation patterns and to identify useful traits in taxonomic differentiation, so that along with their morphology can be achieved concise criteria that help in vegetative identification. The leaves were cleared, stained and photographed. Venation patterns of second, third, fourth and fifth order were described and illustrated for the studied species, which showed brochidodromous or eucamptodromous-brochidodromous secondary venation pattern, except Cryptocarya aschersoniana and Ocotea aciphylla that presented brochidodromous prominulous-reticulate venation. Arcole density was found to be a good taxonomic character, which did not happen with the number of sides that they have. The concepts of the venule nodes and branches and the criteria for the classification of its branches were proposed. Most species have branched venules. The analyzed characters together with the morphological ones, such as margin shape and presence or absence of domatia, allowed the differentiation of the studied species, demonstrating the clear importance of leaf architecture in the taxonomic recognition of specimens in a vegetative state.