Anthesis and Floral Senescence in Chlorogalum pomeridianum (Liliaceae)

Flowers of the soap-plant, Chlorogalum pomeridianum (DC.) Kunth., open for a few hours on only one day. The flowers open rapidly in the late afternoon, produce nectar, and close some 6-8 hr later. As the time of anthesis nears, the tepals become contorted, and progressively larger cavities appear in the tepal mesophyll. Multicellular trichomes at the tips of the tepals increase in length, untangle, and allow the flowers to spring open. Senescence is accompanied by the breakdown of mesophyll cells and by increased ethylene production as the perianth segments twist together and become deliquescent. Anthesis has a weak but discernible rhythmic component and is strongly influenced by alternating light and dark periods. Experiments showed that the length of the uninterrupted light period is of primary importance in the control of anthesis.