This cell wall is easily modified, so its true properties are obtained only from new healthy spores. These can be obtained in the field where samples are lucky enough to capture newly-formed spores, but we don't see this happening often enough in our experience. It seems like no matter what preservative is used to store spores long-term, all cause significant changes in spore morphology. This is a tough one. With cell death, some structural disintegration occurs regardless of the environment in which spores are stored.
Spores stay alive and hence retain much of their structure.
This applies even to Gigaspora spores, which discolor quickly as a result of any physical manipulation. We ship carefully selected spores for molecular studies in such an environment. The hardest genus in which to identify species seems to be Glomus . The differences between them don't seem to be that great. Not that are morphological.