246 Prof. Dr. 0. Mereschkovsky's Diagnoses 



XXVI. — Diagnoses of some Lichens. 

 By ProF. Dr. C Mereschkovsky. 



During the last ten years I have described, in various publi- 

 cations, quite a number of new lichens. As, with a few 

 exceptions, I did not conform with the international con- 

 vention requiring a Latin diagnosis, I liave considered it 

 desirable to add here to my previous descriptions in Russian 

 or French short Latin diagnoses for the greater number of 

 new forms. 



All my collections and notes having been left in Russia, I 

 regret that in some cases tlie diagnoses are not so com[)lete as 

 they might be. 



Usnea floridcij var. divaricata, Mer. 

 Mereschkovsky, Addit. Lichenogr. Ross, i., Oest. Bot. Zeitschr. 1921. 



Thallus mediocris, circiter 7-8 centim. longus, erectus, ramis divari- 

 catis, fibrillis numerosis ut in Usnea harhata typica munitis. 



Spec. orig. (numeros.)'^ in herb, nieo Kazani. 

 Rossia Media, Esthlandia. 



Usnea hirta, forma mhiutissitna, Mer. 



Mereschkovsky, Beitr. z. Kenntn. Flecht. Reval, Kazan, 1909, p. 10 ; 

 id. Lich. Rossiae exsicc. no. 53. 



Thallus minutus, 2-3 centim. hand superans, pulvinulas baud 

 formans, parce sorediatus vel nudiis, semper sterilis. 



Spee. orig. (numeros.) in herb, meo Kazani. 

 Rossia Media, Fennia, Tauria. Etiam in Gallia! et 

 Helvetia! 



Usnea plicata, forma vagans^ Mer. 



Mereschkovsky, Beitr. z. Kenntu. Flecht. Reval, Kazan, 1909, 



Thallus elongatus, subscabrosus, liberus, substrate baud affixus. 



Spec. orig. in herb, meo Kazani. 



Tiie absence of any trace of damage shows that they are 

 not simply fragments torn off from normal specimens. 

 Esthland ; Reval, living on trunks of Pitius. 



* " (numeros.) "' means at least twenty good, identified specimens ; 

 " (numeroeissim.) " about one hundred specimens. 



