Phylogenetic Tree

    The characters recorded for each species were also used to construct a species phylogeny. 13 characters were utilized to classify 29 species, including leaf sheathing reticulation, flower position, flower type, leaf underside color, presence of hair on the leaf sheath, leaf underside, and leaf margins, petiole length, ligule length and shape, presence of pulvinus or stilt roots, and bract spacing. The tree was constructed with the assumption of maximum parsimony using the program Mesquite. The taxa were color-coded according to genus name, if they could be identified to that level, and the tree was chosen that most closely grouped known members of the same genus. The resolution obtained was very low, with most of the groupings polytomies.

     However, resolution was sufficient to make some hypotheses about the evolution of the different characters in the family. For example, several indepedent origins were found for the presence of hair on vegetative structures and the pulvinus, ligule shape, petiole length, ligule size, and leaf underside color. There was one origin found for white leaf reticulation, in the Hornstedtia, and one origin of each flower type and each flower location. However, the presence of so many polytomies in the tree suggests that many of these characters are not homologous. This high instance of convergence makes these hypotheses somewhat poorly supported, without the addition of more taxa and characters.



Character Matrix