MORPHOLOGY, INHERITANCE, AND EVOLUTIONARY SIGNIFICANCE OF SEX REVERSAL IN TRIPSACUM DACTYLOIDES (POACEAE)

Inflorescences of Tripsacum dactyloides (L.) L. (Andropogoneae) are characterized by single female spikelets at one to several basal nodes and paired male spikelets at several nodes above them on each raceme. Female spikelets are one‐flowered and male spikelets are two‐flowered. A sex form variant was found in a wild population in north central Kansas and classified as T. dactyloides (L.) L. forma prolificum Dayton et Dewald. The variant of this native distant relative of maize ( Zea mays L. spp. mays) differs from the normal form by having both pistillate and perfect rather than staminate spikelets in the terminal (tassel) portion of the inflorescence and by having two functional pistillate florets in the basal spikelets instead of one. A recessive major gene at a single locus regulates the change of the inflorescence from monoecious to gynomonoecious.