BY JOHN' SHIRLEY, B.SC. 



11 



than the rhizinre, which are finer than u^ual," Dr. S., 

 Scott. Nat., Jan. 1878. 



* * * Medulla white (K yellow C — ). 



13. P. perlata, 



Thallus orbicular, greyish-glaucous, membranaceous, fre- 

 quently albo - sorediferous especially at margins, dried 

 specimens darker above than usual in Parmelias, central 

 parts in somewhat inflated convolutions, laciniate-lobate, 

 imbricate, with crisped curled margins, latter naked or 

 * Sn. ciliate ; brownish-black below, rhizinose, here and there 

 naked, paler towards margins. Apothecia raised, at times 

 turbinate : margin thin, entire, inflexed ; disk chestnut 

 coloured or olive-brown, concave. Spores simple, broadly 

 ellipsoid or ellipsoid-oblong, colourless, *015 x -0075 m.m. 

 Thecjfi 8-sporedj blue with iodine. "0625 x 'Q25 m m. Sper- 

 matid acicular. 



Syn. — P. fuscescens, Hook. P. Zollinger!, Hcpp. 



Hib. — Common. 



P. perlata v. obsolete nigro-fibrillosa, C.K. 



Differs from the type in the brown-black under surface 

 K showing itself very slightly and indistinctly fibrillose. 



******* Medulla white (C red) 



14. P. olivetorum, Ach. 



Thallus orbicular, pale shining grey with a faint glaucous 

 tint, lobes imbricated and obscure, lobules broad, rounded, 

 with narrow linear junctions to the main lobes, ending in 

 few rounded dentate laciniae ; margins blaek-ciliate, cilia 

 few, old lobes with white-soredioid margins ; medulla C 

 crimson ; under surface black, smooth and naked all round 

 L. the margins. Apothecia not seen. Leighton says — 

 " Externally similar to the sorediate states of P. perlata, but 

 distinguished by the chemical reaction of the white medulla, 

 which is tinged red by C (but more definitely by applying C, 

 then K, then C again). 



Syn. — P. perlata f. olivetorum, Ach. 



