r.ICHKNOLOGY OF ICELAND 155 



degenerans, uncialis, Thamnolia vermicular is, Cornicularia acnleata, 

 Bryopogon jnbatns v. nitidulns, Sphcerophorns fragilis\ they play ex- 

 actly the same role as do apical haptera put into other species. 



Primary-scale haptera I found only in Cladonia foliacea. By 

 means of them the primary scales of long duration which die away 

 at the base, are attached to one another; no parasitic relation arises 

 by this attachment. 



Podetium-scale haptera I found only in Cladonia cornuta. 

 By means of them the podetia are attached to one another, the scales 

 of the one podetium attaching themselves to the wall of another 

 podetium of the same species; no parasitic relation arises by this 

 attachment. 



When procumbent podetia are buried in the ground, they die. 

 No species known to me can endure being covered with earth for 

 a long time. First the gonidia appear to die, sometimes after a short 

 period of intense division, which is probably occasioned by the 

 increased dampness. Then the lichen-hyphre die, the walls, as a 

 rule, turning brown. 



The fruticose earth-lichens are propagated in a widely different 

 manner according to their morphological structure. Hypothallus- 

 wanderers very commonly bear fruit, and are propagated, no doubt 

 as a rule, by ascospores. Some of them are propagated far more 

 frequently by soredia, and in that case apothecia are much rarer 

 in them (Cladonia fimbriata, deformis), so that in such species there 

 appears to exist a correlation between these two modes of propa- 

 gation. In others again these two modes of propagation appear to 

 be equally common, a quantity of soredia and apothecia being de- 

 veloped on the same individual. However it requires to be more 

 closely investigated, whether the asci in strongly soredia -bearing 

 individuals are empty, as they frequently are in Cladonia. 



In the podetium-w^anderers propagation takes place in several 

 cases by the breaking off of fragments of podetia which are then 

 carried away by the wind to other places where they form new 

 tufts. This has already been described by Wainio (1808) and after- 

 wards mentioned by Mentz (1900) and Galloe (1913 and 1918). 



Species of Stereocaulon do not appear to be able to propagate 

 themselves in this way, as podetia-fragments have not yet been 

 observed to put out haptera into the ground. On the other hand, 

 they are often found bearing apothecia. 



Of fruticose earth-lichens Iceland has the following: 



