H. Bischler et Mc. Boisselierdubayle, VARIATION IN A POLYPLOID, DIOECIOUS LIVERWORT, MARCHANTIA-GLOBOSA, American journal of botany, 80(8), 1993, pp. 953-958
This study was undertaken in order to determine the population structu
re in a tropical, geographically isolated liverwort, Marchantia globos
a Brid. ex Web., a thallose species endemic to the Mascarenes and Como
ro Islands. A survey of numerous populations on Reunion showed M. glob
osa to be ecologically tolerant and morphologically quite variable. Th
e morphological differences between populations could only be explaine
d by a size effect, due principally to altitude. Neither cytological n
or electrophoretic analyses revealed any genetic basis for distinguish
ing subpopulations. In spite of an apparently high reproductive effort
, sexual structures being produced abundantly, few spores reach maturi
ty. No electrophoretically detectable genetic polymorphism was found.
Morphological variation appears to result from phenotypic plasticity.