319 



12 (a). Alectoria jubata (L.). 



Oii bouldcrs iiiid pcbbles :iinon<> mosses. Rather t're([iient in various 

 forms ^H., !). 



The paler thallus [implexa Hoffm.) changes into yellow when 



treated with hydrate of potash, but the darker one [chahjheiformis 



Ach.) does not change. If these colours have specific vahie, it 



shall be quite unnecessary to await the chemical reaction, because 



the natural colours show siniilar difTerences. 



13 (b). A. bicolor (Ehrh.). 

 S t r 6 m 6 : Kirkcbofjæld (R.). 



14. A. nigricans (Ach.). 



On rocks and ground. S trom 6: (lliversrejn R.); Videro (!); 

 Ostero: Næs (R.). 



Å. ochroleuca has not been found in the Færoes, and in Scot- 

 land it has been met with in one locality only, while A. nigricans 

 often occurs there on the mountains, and usually abundanth^ 

 Perhaps the latter species can better endure strong cold as well as 

 damp air, since it is also rather common in Spilzbergen and East 

 Greenland, while ochroleuca is very rare. 



15. Cornicuiaria aculeata (Ehrh.). 



On dry gravelly ground, common (R., !). 



16. C. tristis (Web.). 



S. E. side of I\ u n 6 (!). 



Cystocoleus rupestris (Pers.). C. ebeneus Thw., Racodinm Pers. 

 Stromo: Kirkebofjæld (!). 



17 (a). Ramalina scopulorum (Retz.). 



On rocks by the sea, common and abundant ;R., !\ 

 Has sometimes a vigorous growth, but more often the thallus 

 is weakly developed, almost round. Neither the cortex nor medulla 

 gives any distinct reaction when treated with hydrate of potash, 

 and consequently the specimens as not being colorated ought to 

 be referred to K. cuspidata Nyl. They have often soredia as the 

 foUowing species. 



18 (b). R. farinacea (L.). 



On the mountains, and in the interior of tlie Islands, common ,R., !). 



In the Herb. Horti Hafn. ihere is a specimen from the Færoes, 

 named var. canalicnlata (Fl. dan. 263G, 2), and certainly approaching 

 this variety. Other specimens collected bj' Simmons and named 

 R. siibfarinacea Nyl.?, which when treated with hydrate of potash 



