A Lichenological Legacy – Festschrift Thomas H

15 Medulla PD+ yellow (2,7-dichloropsoromate and 2,7-dichloronorpsoromate) ..
....................................................................................................... P. swinscowii
15' Medulla PD+ orange ...................................................................................... 16
16 Thallus containing mainly phyllopsorin and chlorophyllopsorin .......................
................................................................................................... P. ochroxantha
16' Thallus containing argopsin and often norargopsin ....................................... 17
17 Squamules medium brown to dark brown, shiny, with a concolorous margin;
isidia more or less flattened; ascospores 5.5–7.5 μm long; norargopsin
sometimes absent .................................................................... P. phaeobyssina
17' Squamules greenish brown, often with a paler margin; isidia cylindrical;
ascospores 7.5–10.5 μm long; norargopsin always present ........... P. santensis
18 Thallus crustose, apothecia common, vegetative diaspores absent ............... 19
18' Thallus squamulose, apothecia and vegetative diaspores present or absent .......
......................................................................................................................... 21
19 Ascospores narrowly ellipsoid, 6–8 2.5–3 μm; exciple and lower part of
medulla containing orange crystals dissolving in K, K+ purple (norsolorinic
acid) ...................................................................................... P. pyrrhomelaena
19' Ascospores acicular, more than 19 μm long; exciple and medulla not
containing orange crystals .............................................................................. 20
20 Apothecia yellowish brown; ascospores 19–30 μm long; thallus containing
atranorin ........................................................................................... P. cognata
20' Apothecia reddish brown; ascospores 28–41 μm long; thallus lacking lichen
substances ......................................................................................... P. pertexta
21 Thallus lacking lichen substances .................................................................. 22
21' Thallus containing lichen substances ............................................................. 30
22 Ascospores acicular, more than 19 µm long .................................................. 23
22' Ascospores ellipsoid to bacilliform, up to 18 µm long .................................. 24
23 Squamules ascending, deeply incised or divided, often with vein-like
supportive tissue ............................................................................... P. lacerata
23' Squamules mostly adnate, crenulate to lobed, without vein-like tissue ..............
................................................................................................. P. microphyllina
24 Thallus with phyllidia in inner part and elongated, more less radiating
marginal squamules ....................................................................... P. parvifolia
24' Thallus without phyllidia (but sometimes with lacinules, i.e. apical sections of
squamules breaking off), marginal squamules of various shapes .................. 25
25 Squamules mostly adnate, without lacinules ................................................. 26
25' Squamules mostly ascending, lacinulate ........................................................ 28
26 Ascospores ellipsoid, up to 6.5 µm long .................................. P. microsperma
26' Ascospores ellipsoid to fusiform, more than 7 µm long ................................ 27
27 Thallus composed of large, up 0.5(–1) mm wide squamules ..... P. breviuscula
27' Thallus composed of small, up to 0.1 mm wide squamules ................ P. minor
28 Hypothecium evenly dark reddish brown, K+ purple ............... P. chlorophaea
28' Hypothecium colourless to yellowish brown, K– .......................................... 29
29 Thallus consisting of squamules ascending from a more or less continuous
crust of adnate areolae; prothallus thick, reddish brown ............ P. longiuscula
29' Thallus consisting of ascending squamules only; prothallus white or reddish
brown, thin or thick .......................................................................... P. confusa
349
eschweizerbart_xxx