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 . . . .