SYSTEMATIC EMBRYOLOGY OF THE ARACEAE

Embryological data of systematic significance to the family Araceae are reviewed and analyzed, with special attention given to the determination of character-state polarities. Character-states considered primitive within the family include: presence of endothecial thickenings; binucleate, starchless pollen; anatropous, crassinucellate ovules with a thick nucellar cap and a single, unbranched funicular bundle; solanad or caryophyllad embryogeny; helobial endosperm development, with 2-8 cells in the chalazal chamber and ab initio cellular division in the micropylar chamber; and endosperm present in ripe seeds. The phylogenetic implications of these conclusions are discussed, and promising avenues for future research are indicated.