Floral bract function, flowering process and breeding systems of Sarcandra and Chloranthus (Chloranthaceae)

Structure and function of floral bracts, anthesis and breeding systems were investigated in greenhouse plants of Sarcandra chloranthoides, Sarcandra glabra, and Chloranthus spicatus (Chloranthaceae). In early developmental stages the floral bract replaces the lacking perianth as a protective structure by enclosing the floral organs completely in a pocket-like structure, which is formed by the u-shaped attachment zone of the floral bract to the spike axis. The floral bract has a tip with an epithem tissue, from which traces of secretion seem to be released by the stomata. All species investigated have protogynous and longlasting flowers. The female phase begins five to seven days earlier than the male phase. It continues during the male phase and for some time thereafter. The male phase lasts between one day (Chloranthus spicatus) and seven days (Sarcandra chloranthoides). This is the first study on breeding systems of Chloranthaceae. They are of special interest in such a basal family of the angiosperms. Although the investigated Sarcandra and Chloranthus species have similar flowers with entomophilous features, surprisingly their breeding systems are diverse: Sarcandra glabra is self-compatible, S. chloranthoides is agamospermous and Chloranthus spicatus is self-incompatible.