Keys to the macrolichens and checklist of the lichens and ...

24b. Isidia pale-tipped; medulla KC-; malonprotocetraric acid absent ......... P. pacificum
25a. Medulla intense sulphur yellow or orange throughout; vulpinic acid present.
............................................................................................................P. sulphuratum
25b. Medulla mostly white ............................................................................................ 26
26a. Lichexanthone (UV+ gold) and salazinic acid present........................P. ultralucens
26b. Lichexanthone and salazinic acid absent ............................................................... 27
27a. Isidia wart-like, ciliate ........................................................................ P. verrucatum
27b. Isidia cylindrical, coralloid-branched, becoming sorediate and/or ciliate; not wartlike..........................................................................................................................
28
28a. Isidia eciliate .......................................................................................................... 29
28b. Isidia ciliate............................................................................................................ 30
29a. Isidia becoming ± subsorediate; medulla KC-, P-; diffractaic acid present.
........................................................................................................ P. isidioinsuetum
29b. Isidia intact; medulla KC+ pink-red, P+ deep orange-red; protocetraric acid
present.............................................................................................P. kaisenikianum
30a. Isidia eventually becoming granular- sorediate ..................................................... 31
30b. Isidia ±fragile but not becoming sorediate............................................................. 32
31a. Medulla K+ bright yellow; stictic acid present........................................ P. crinitum
31b. Medulla K-; alectoronic, a-collatolic acids present ................................. P. mellissii
32a. Cilia mostly to 1 mm long; lobules present; alectoronic and a-collatolic acids
present...............................................................................................P. nanfongensis
32b. Cilia greater than 1 mm long; lobules absent; alectoronic and a-collatolic acids
absent ..................................................................................................................... 33
33a. Medulla C-, KC- or KC+ brownish, P+ deep orange-red; fumarprotocetraric and
succinprotocetraric acids present; cilia 2-5 mm long ....................... P. acrotrychum
33b. Medulla C-, KC+ reddish, P+ brick red; protocetraric and protolichesterinic acids
present; cilia 1.5-3 mm long ...........................................................P. subcorallinum
34a. Thallus pustulate, ±sorediate ................................................................................. 35
34b. Thallus sorediate; pustules absent.......................................................................... 36
35a. Medulla pale yellow (eumitrin A1); pustules esorediate ......................P. kainantum
35b. Medulla white; pustules sorediate......................................................... P. madilynae
36a. Lobes eciliate ......................................................................................................... 37
36b. Lobes ciliate........................................................................................................... 42
37a. Medulla K+ bright yellow turning bright red; salazinic acid present .. P. cristiferum
37b. Medulla K- or K+ dirty yellow; salazinic acid absent ........................................... 38
38a. Medulla P-; fatty acid present (praesorediosic acid).................... P. praesorediosum