146 



OLAF GALL0E 



Cetraria cucullata Bell. 



hiascens (Fr.) Th. Fr. 

 nivalis (L.) Ach. 

 Dermatocarpon cinereum Pers. 

 hepalicum Ach. 

 rufescens Ach. 

 Leplogium lacerum Ach. 

 scotinuin Ach. 

 Nephroma arcticum L. 



expallidum Nyl. 

 tomentosum (Hofl'm.) Nyl. 

 Pannaria microphylla Nyl. 

 Parraelia lanata Wallr. 



Peltigera aphtosa L. 



canina (L.) Fr. 



horizontalis L. 



lepidophora Nyl. 



malacea (Ach.) Fr. 



polydactyla(Neck.)Hotlm. 



rufescens Fr. 



venosa (L.) Hoffm. 

 Physcia pulverulenta Nyl. 



(v. muscigena). 

 Solorina bispora Nyl. 



crocea Ach. 



saccata L. 



The Fruticose earth-lichens. Three types may be distin- 

 guished, which are however connected by intermediate forms, 

 namely, Hypothallus-wanderers, Podetium-wanderers and 

 Primary-scale-wanderers, which have been exhaustively des- 

 cribed and for the first time established by me in 1913. From 

 these groups I quote as examples: 



H y p o t h a 1 1 u s - w a n d e r e r s : Stereocaulon condensatum, Cladonia 

 papillaria, C. pyxidata, C. pityrea, C. fimbriata, C. squamosa, C. cris- 

 pata, C. cornuta, C. macilenta, C. Floerkeana, C. coccifera, C. deformis, 

 C. verticillata (see ligs. in Forb. Unders., 1913). 



Podetium-wanderers: Stereocaulon tomentosnm, S. evolutum, 

 S. coralloides, S. paschale, Dufourea arctica, I), muricata, Siphnla cera- 

 tites, Cladonia degenerans, C. gradlis, C. furcata, C. rangiformis, C. 11/1- 

 cialis, C. rangiferina , Thamnolia vennicularis , Alectoria ochrolenca, 

 Cornicularia aculeata, Bryopogon jnbatns v. nitidnhis, Sphcerophorus 

 fragilis (see figs, in Forb. Unders., 1913). 



Primary-scale-wanderers: Cladonia foliacea (see figs, in 

 Forb. Unders., 1913). 



As an example of the structure of a hypothallus-wanderer, 

 a description of Cladonia pyxidata will suffice. When the spore in 

 this species germinates, it gives rise to a mycelium which spreads 

 out radially in the ground (Dan. Lik. 0k., fig. 39 a), and is called a 

 hypothallus. Wherever these purely mycelial hyphse encounter Pleiiro- 

 coccus-algse on the surface of the ground, they establish as has 

 already been described by Krabbe (1891) and Wainio (1898), - 

 a connection with these latter, and form lichens. We may then, on 

 a somewhat older hypothallus, distinguish between the purely my- 

 celial hyphae, which have not as yet begun their lichen-formation, 

 and within these (nearer to the germinating point) a belt, where the 



