Fossil endogonaceous chlamydospores are described from the aerial axes and roots of
several Paleozoic plants preserved in calcilutite nodules and calcareous coal balls. Specimens
come from six Paleozoic localities extending from the uppermost Lower Devonian through
the Upper Pennsylvanian. Although fossil chlamydospores are markedly similar to the modern
Endogonaceae in transmitted light, ultrastructural comparisons have not previously been
made. The fine structure of the walls of these spores is consistent with past interpretations
which relate them to the modern Endogonaceae, but thorough comparisons cannot be made
due to the lack of comparable ultrastructural information from extant VA mycorrhizae. The
evidence from mycorrhizal associations in the fossil record is evaluated
