Prothallus, Protothallus, first stages of hyphal growth; [cf. hypothallus], [71].
Pycnidiospores, stylospores borne in pycnidia, [198] et passim.
Pycnidium, roundish fructification, usually with an opening at the apex, containing sporophores and stylospores; [cf. spermogonium], [192 et seq.]
Pyrenolichens, in which the fructification is a closed perithecium, [173] et passim.
Radiate thallus, the tissues radiate from a centre, [98 et seq.]
Rhagadiose, deeply chinked, [74]; [cf. rimose].
Rhizina, attaching “rootlet,” [92-94].
Rimose, Rimulose, cleft or chinked into areolae, [73].
Rimose-diffract, widely cracked or chinked, [74].