Factors Regulating the Initial Development of Gemmae in Marchantia polymorpha

processes. The lenticular gemmnae are produced in receptacles that are attached to the thallus over relatively wide areas. The wall of the receptacle is multi-layered at its base, but becomes thinner upward and divides into five triangular lobes. The gemmae develop on papillae which project from the epidermal tissue at the bottom of the receptacle and grow upward supported by club-like hairs which excrete slime. When they are detached from their short stalks, the gemmae are yet incompletely developed. Both sides of the gemmae are morphologically and physiologically identical. In addition to cells containing chloroplast and starch, there are oil bodies and, in the center of the gemma, rhizoid initials. The germination of the gemma involves two processes: the appearance of rhizoids and the initiation of growth at the growth centers. The germination of the gemmae rarely takes place in