KRAYESKY, DAVID M. and BARBARA J. CRANDALL-STOTLER.* Department of Plant Biology, Southern Illinois University, Carbondale, IL 62901. - An SEM Photo Atlas of Spore Terminology in the Fossombroniineae.
Species delimitations and taxonomic groupings within the
Fossombroniineae have traditionally relied on variations in spore wall
architecture and consequently, many decriptors of spore wall
morphology have been published. In most studies spores have been
described on the basis of features resolved at the level of optical
microscopy. With the increased resolution of SEM, many of the early
descriptors are no longer applicable. For example, the epithet of
Fossombronia foveolata Lindb. presumably described a foveolate
distal spore wall surface, which in more recent times has been
described by various other authors as reticulate, areolate, or even
alveolate. To resolve the inconsistencies in spore wall terminology,
we have compiled representative SEM micrographs of both distal and
proximal spore wall architectures, prepared as part of a worldwide
monograph of the Fossombroniineae. A variety of modern and classical
treatments of pollen and spore morphology were consulted to identify
the most appropriate descriptor for each of the major architectural
patterns found in the group. These results are presented as a photo
atlas, in which ten major distal face architectural designs are
recognized. While there is less variation in proximal face designs,
the systematically significant features of this face will also be
presented.
Key words: Fossombroniineae, liverwort spores, spore wall architecture, terminology