1a.   Hyphae with clamps

2

 1b.   Hyphae without clamps

3

 2a.   Spores 6-7.5 µm

P. humicola

 2b.   Spores 9-11 µm and chlamydospores at the rhizomorphs

P. vepallidospora

 3a.   Spores brown, subicular hyphae, brown (P. tristis complex)

4

 3b.   Spores hyaline to yellowish, subicular hyphae hyaline to pale brownish

11

 4a.    Hymenial elements turning in KOH greenish or bluish to black (cyanescent)

6

 4b.    Hymenial elements not cyanescent

5

 5a.    Spore ornaments 1.2- 2 µm high

P. umbrinascens

 5b.    Spore ornaments 0.7-1.2 µm high

P. umbrina

 6a.    all subicular hyphae narrower than 4.5 µm

7

 6b.    most subicular hyphae than 4.5 µm

 9

 7a.    Rhizomorphs dimitic

P. atrofusca

 7b.    Rhizomorphs monomitic

8

 8a.    Spores Ø 7-8 µm, hymenial elements weakly cyanescent

P. rotundispora

 8b.    Spores Ø 8-10 µm, hymenial elements strong cyanescent

P. media

 9a.    Spores Ø < 8 µm

P. sciastra

 9b.    Spores Ø > 8 µm

10

10a.   Spores Ø 9-10,5 µm

P. pluriloba

10b.   Spores Ø 8-9 µm

P. tristis

11a.   with brown chlamydospores at the rhizomorphs

P. rhizopunctata

11b.   Chlamydospores absent

12

12a.   two size of spores present, 5,5-7 µm and 8-11 µm, subiculum dark brown to bluish-black         

P. nigra

12b.   only one size of spores present, subiculum grey to pale brownish

13

13a.   Hymenial elements strong cyanescent, basidia to 100 µm long, hymenophore greenish-bluish

P. flavovirens

13b.   Hymenial elements not or only weakly cyanescent

14

14a.   Hymenophore grey, subiculum darker than hymenophore

15

14b.   Hymenophore brownish, subiculum paler than hymenophore

P. mucidula

15a.   Spores lobed, bifurcate spines shortly and broad

P. griseopergamacae

15b.   Spores not lobed, spines long with forked apex

P. molybdaea