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1. A specialized multicellular unit of vegetative reproduction found in certain mosses and liverworts, and in Psilotum. It may take various forms, from being disc- or platelike to being filamentous or heart shaped. When separated from the parent it develops into a new individual identical to the parent. Gemma cups may be formed where several gemmae are produced on a protective receptacle, as seen in the moss Tetraphis pellucida. Clusters of gemmae may also be seen at leaf tips or in the leaf axils, on specialized stalks or pseudopodia, and on rhizoids. Reproduction by gemmation occurs more frequently than spore formation and in some species it is the only form of reproduction seen.
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