352 BOTANY OF SOCOTRA. 



1. STICTA. 



Sticta, Nyl. Syn. 351. 



Sticta, Ach. pr. p. et Auct. pr. p. 



A beautiful genus, dispersed over all parts of the globe except the 

 northern. Distinguished from Stictina only by its true ordinary globular and 

 simple gonidia having a fresh green not a bluish tint. An oblique section of 

 the thallus of a Stictina shows a bluish hypoderma layer of cells ; in Sticta this 

 is absent. 



S. aurata, Ach. Meth. p. 277. 



Socotra. Ad ramulos supra Wadi Kischen alt. 1000 m. (sterilis). 

 Schweinf. 



Distrib. The most common species of the genus in tropical and sub- 

 tropical regions, and also found in the western parts of temperate Europe. 



2. STICTINA. 



Stictina, Nyl. Syn. 333. 



Sticta, Ach. pr. p. et Auct. pr. p. 



A genus with numerous species forming parallel series to the corresponding 

 series of Sticta, having the same geographical distribution, but with a larger 

 representation in Europe. It often happens that species of the two genera have 

 the strongest resemblance. In both genera the spores are sooner or later 

 coloured fuscescent or brown. 



S. Mougeotiana, Nyl. Syn. p. 340. 



Socotra. Ad ramulos cum prsecedente, et in Scheheli Kegel supra 

 Tamarida alt. 1250 m. Schweinf. 



Distrib. Eound in many other tropical or at least warmer parts of the 

 old world, and in French Guiana. 



3. THELOSCHISTES. 



Theloschistes, Norm. Conat. Prsemiss. 17 ; Th. Fries Heterol. 51 ; Tuck. Gen. 18. 



Physcia, Nyl. Syn. 406, pr. p. 



Xanthorioc, sect. Theloschistes, Stitzb. Beitr. 173. 



Parmelios, sp. Auct. 



A small genus with generally much dispersed and exceedingly common 

 species. 



T. flavicans, Norm. Conat. Prsemiss. Gen. Lich. p. 17. 



Socotra. B.C.S. n. 1449 pro parte. Ad ramos supra Wadi Kischen alt. 

 1000 m. Schweinf. 



