I00 BERNT LYNGE. M.-N. Kl. 



Physcia caesia f. melops (Dur.) WAIN. Pitlekai (1909) P- 68. HARMAND 



Lich. France (1909) P- 6 3- 



An syn. Lichen alboniger SCHLEICHER PI. crypt, helvet. No. 71 



(1806), and 



Physcia albonigra (SCHLEICH.) DALLA TORRE et SARNTHEIM Die Flech- 

 ten von Tirol (1902) p. 164, (ubi syn.). 



Tab. I, fig. 4. 



Exsic. According to DALLA TORRE et SARNTHEIM 1. c. ARNOLD No. 

 897 belongs to our species; which must be a misprint (ARNOLD 897: 

 Lithoicea viridula (SCHRAD.) var. elevata NYL.) ARNOLD no. 1648 (Parmelia 

 albonigra SCHL.) diifers considerably from our plant in having an entirely 

 white thallus of a Ph. aipolia-\ike exterior. I have seen neither the speci- 

 mens of DUFOUR nor those of SCHLEICHER. The Norwegian material was 

 determined by the late, eminent Finnish lichenologist, Mr. LANG. 



Thallus moderate or large, orbicular, diam. 6 10 cm., loosely 

 adnate, firm. Laciniae contiguous, often with imbricate apices, distinctly 

 stellate and continuous from the centre to the circumference, convex, 

 rugulose or smooth, with indistinct pale spots, linear, narrow : 0,5 0,7 mm. 

 broad, with undulate outlines, multifid, pinnately branched; bran- 

 ches more or less divergent with acute angles. Thallus without soredia, 

 isidia or pruina. About the centre we may find small, papillary, secondary 

 laciniae, which fil up the interstices between the great primary laciniae. 

 Colour ash-grey with a tinge of violet, under side pale brown or 

 greyish-brown, nearly covered by long, dark or even black, branched 

 rhizinae. 



The impellucid part of the upper cortex is darker, and the under 

 cortex paler than in Ph. caesia. In other respects the thallus anatomy is 

 as in Ph. caesia. 



Apothecia very numerous, sometimes covering the central part of the 

 thallus, they are sessile, not appressed, sometimes very shortly pedicellate. They 

 are small, diam. i 1,5 mm., rounded or angulose, due to mutual pressure, 

 with persistent, at length crenate margin and plane, epruinose disc. Re- 

 ceptacle of the same colour as the thallus or a little paler, smooth. Cortex 

 at the exterior part pale brownish with its hyphae perpendicular to the 

 surface, otherwise uncoloured. The position of the gonidia, form of hyme- 

 nium and paraphyses as in Ph. caesia, only that the paraphyses are less 

 incrassate. Spores not constricted at the centre, otherwise as in Ph. caesia, 

 16,6 20,5 |U 1 n g, 7.9 8,6 ti thick. 



