Abstract
In the Ascomycete Sphaerostilbe repens, where calcium is necessary for the differentiation of aggregated organs, microlocalization of calcium was determined both in undifferentiated mycelium and in rhizomorphs. In every case cell walls contained high calcium concentrations. Mucilaginous compounds around cells also contain this cation but at a lower level.In the vegetative mycelium, Woronin bodies and particularily mitochondria accumulated calcium. In the vacuoles of rhizomorph cells, calcium concentration was low.Calcium location in cell walls suggests that this element could play a role in cell-to-cell adhesion.