AN ANATOMIC-SYSTEMATIC STUDY OF THE CLASSICAL TRIBE FESTUCEAE (GRAMINEAE)

Using the classical tribe Festuceae as a frame of reference, 135 grass genera have been examined in an effort to determine natural generic relationships which often have been obscured by parallel and convergent evolution. Studies of embryo and leaf structure, ligules, lodicules, and lemmas have greatly enlarged, verified, and nearly completed existing evidence that the classical concept of the Festuceae is highly artificial and that the tribe contains many genera which are only remotely related. A more nearly phylogenetic system is achieved when more than two-thirds of these genera are distributed among 4 major groups, which may be worthy of subfamily rank: 55 genera are retained in the festucoid group, 46 are moved to the eragrostoid, 2 to the bambusoid, 13 to the arundoid, and 8 to a recently designated group labelled the centothecoid. Three genera remain unplaced; and material was unavailable or insufficient to make accurate determinations for 8 genera.