Revision of the Genus <i>Christensenia</i>

Abstract

The present revision of Christensenia is the first for this genus. Observations of exter­ nal and interna!foliar morphology, with particular emphasis on valid taxonomic charac­ ters of pinna indument and epidermis and soral paraphyses have shown that the taxa of the genus are C. aesculifolia Blume subsp. aesculifolia and subsp. korthalsii (de Vriese) Rolleri and C. lobbiana (de Vriese) Rolleri. Synangium outline, number of sporangia per synangium, and spore morphology are not systematically important. The morphology and physiology of adult porocyclocytic stomates and the presence, chemical composition, and density of microprojections of the mesophyll cell walls are adaptive and vary according to ambient humidity.