G. ambigua has larger spores that are about 22-30 m long.

Smith did mention that "the large spores are unusual for the genus Pluteus" .

It has larger spores than A. abruptibulbus, typically 7.0-9.2 by 4.4-5.5 m.

One kind, the megasporangium, produces only a single large spore (a megaspore).

Producing large dark unicellular spores also helps survival.

Microscopically, the latter species has larger spores, ranging from 8-12 by 5.5-9 μm.

M. cerebralis has many diverse stages ranging from single cells to relatively large spores, not all of which have been studied in detail.

The large spores are spindle-shaped and measure 17-20 μm long by 5.5-6 μm wide.

I. obtusiuscula also has larger spores of a different shape, and they are a darker colour, owing to their thick cell walls.

However, the fruit bodies of H. pustulatus are smaller, and it produces larger spores (11-14 m long).