The upper limit of the spore size of A. asiaticus is larger than that of its more common relative, ranging from 8.75-15.2 μm.

Since the colors and sizes of M. acicula and M. adonis are similar, a microscope is needed to reliably distinguish between them, with spore size and shape being different.

The spore size is approx.

Species may also be distinguished by differences in spore size and shape, although a considerable size range has been noted for C. asprata spores.

This species is very similar in appearance to Hydnellum scrobilatum, and traditionally, largely unreliable microscopic characteristics such as spore size and ornamentation have been used to distinguish between the two.

The mailed anthrax is also astonishingly pure and equivalent (in spore size and concentration) to the best the American Army ever achieved.

The range of its spore sizes are generally larger than A. hygrometricus (upper diameter of 15.2 μm).

Some experts divide Agrocybe pediades into several species, mainly by habitat and microscopic features, such as spore size.

The typical fungal spore size is 1-40 micrometer in length.

The spores of C. stercoreus are roughly spherical and relatively large, with typical dimensions of 20-35 x 20-25 m, although great variability in spore size has been noted.