Anther Number, Anther Apical Appendages, and Pollination Biology of Calyptocarpus vialis Lessing (Heliantheae: Asteraceae)

Abstract

The numbers of disk floret anthers of Calyptocarpus vialis in Wichita County, Texas form a consecutive series of one to four; four anthers (71%) and three anthers (27%) were most common. Three anthers is an unusual, perhaps singular, number for Asteraceae. These florets also have four-lobed corollas. The extruded pollen-mass is enclosed by a vaulted dome created by apical appendages of the anthers that are lanceolate and inflexed. Pollination appears to be via autogamy ( sensu stricto ) for disk florets and (considering each head as a single blossom) facultative autogamy and allogamy (both geitonogamy and xenogamy) for the ray florets.