280 Prof. Dr. C. Meresclikovsky's Diagnoses 



Var. detrita, forma albescens^ Mer. 



Mereschkovsky, /. c. p. 224. 



Thallo sordide albesceiite vel grlseo-albescente. Ad ssepimenta. 



Spec. orig. (numeros.) ibidem. 

 liossia Media (Kazan). 



Forma ni'greseeus, Mer. 

 Mereschkovsky, I. c. 



Thallo obscuro cinereo-nigrescente vel nigrescente ; apot-hecia parva, 

 disco iiigro, undo, margine ititegro. Ad saepimenta. 



Sprc. orig. (numeros.) ibidem. * 



Kossia Media (Kazan). 



Ill order to make the distinction between tlie two allied 

 species — Physcia labrata, Mer., and Physcia virella (Acb.), 

 Mer. — more clear, I oive liere two figures siiowing the peri- 

 })iieral lobes, and below a longitudinal section along a lobe. 

 The darkened parts represent the sorals, being superficial 

 in Ph. virella and terminal or lateral in Ph. labrata. 



Fig. 1. 



Fig. 2. 



~rn ) I \K 



Fig. 1. — Physcia virella (Ach.), Mer. 

 Fig. 2. — Physcia labrata, Mer. 



Physcia obscura, forma dispersa, Mer. 



Mereschkovsky, Contrib. fl. lich^nol. d. envir. d. Kazan, Hedwigia, 

 1919, p. 226. 



Thallo cinereo, sicut in forma typica, seepe valde extenso, laciniis 

 brevibus, sparsis, rosulas haud formans, sorediis destitute ; apo- 

 thecia mediocria vel sat parva, disco fusco-nigricante, nudo, 



