I9l6. No. 8. MONOGRAPH OF THE NORWEGIAN PHYSCIACEAE. 67 



character of sufficient importance to separate var. leucoleiptes from Ph. 

 grisea and to refer it to Ph. pulverulenta . I do not agree with this view. 



In some of the Norwegian specimens the white colour has been 

 preserved over the whole lower face, in others there is a marginal un- 

 coloured zone, whereas the central part is dark. The rhizinae are first 

 coloured, then the adjacent part of the lower cortex, and at last the dark 

 spots become confluent. 



ACHARIUS did not attribute much importance to the colour of the lower 

 cortex. His Parmelia farrea a l is subtus albido fibrillis fusconigris and 

 his var. p alphiphora of the same species is subtus atro-tomentoso. In 

 reality its cortex is also black. HARMAND is also doubtful, for his f. 

 brunnea^ has a face inferieure largement pale, ce n'est que vers la base 

 qu'apparait le brun ou le brun-noiratre, a very correct observation. 



After HUE and HARMAND there would be many parallel varieties of 

 Ph. pulverulenta and Ph. grisea, for almost every one of the Ph. grisea varie- 

 ties here described has specimens with more or less darkened lower face. 



It seems to me that such characters are not suited to separate between 

 different species. We shall have a more natural arrangement, if we refer 

 sorediate varieties to Ph. grisea and esorediate varieties to Ph. pulverulenta. 

 The latter species always has a black lower face, the former a variable 

 colour, in some varieties an entirely or at least partly black lower 

 side, in others an uncoloured one. 



var. detersa is here limited to chestnut or brown plants with a black 

 lower surface. HARMAND'S var. leucoleiptes also comprises plants with 

 whitish pruinose laciniae. 



var. semi farrea (WAIN.) LYNGE comb. nov. 



Physcia (pulverulenta) * * farrea ACHARIUS f. semifarrea WAIN. Adju- 

 menta I (1881) p. 132. 



Physcia pulverulenta var. leucoleiptes f. brunnea HARM. Lich. France 

 (1909) p. 636. 



Ex sic. NORRL. et NYL. Herb. Lich. Fenn. 214. (Ph. muscigena ACH. 

 var. semifarrea WAIN.). CLAUD, et HARM. Lich. Gall. 494 (s. n. Physcia pul- 

 verulenta var. leucoleiptes f. brunnea HARM.). FRIES Lich. Suec. 294. (Parm. 

 pityrea farrea). 



1 Lich. Univ. p. 475. 



2 Lich. France p. 636. 



