Patterns in Evolution in Characters That Define Iris Subgenera and Sections

Subgeneric groups have been circumscribed in Iris based on a small number of morphological characters. Recent DNA sequence data has indicated that several of the subgenera, sections, and series that have previously been delineated are paraphyletic or polyphyletic. The evolution of characters that have traditionally been used to distinguish sub generic and sectional groups within Iris was investigated by mapping these characters on a phylogenetic tree based on matK sequence data. Results indicate that rhizomes are pleisomorphic for the genus and that three bulb types have arisen independently. My analysis shows that sepal beards, sepal crests, and seed arils show extensive homoplasy. Most of the homoplasy seen is associated with the circumscription of polyphyletic subgeneric groups such as the beardless subgenus Limniris. Some additional homoplasy is due to diversity within supported clades or the historical use of a single character in circumscribing more than one subgeneric group.