Spores up to 7 m, ovoid to subellipsoid . P. subarduennensis Singer 2. Spores 7 m or greater, ellipsoid to limoniform . . . . Spores subellipsoid to subamygdaliform, finely verrucose, with a germ pore . . . . P. subattenuata Singer 3.
Spores limoniform, strongly verrucose, mucronate . . . .
P. oligoporpa Singer 1. Clamp connections absent . . . . 4 4. Spores up to 7 m, subglobose to subovoid or subellipsoid . Spores ellipsoid and sometimes with a faint germ pore . . . . Spores amygdaliform to limoniform-mucronate . . . .