M. FOSLIE. [1908 



are not identical at all, but that L. murmanicum actually belongs 

 to L. hreviaxe. 



As I stated in Rem. norlh, Lithoth. p. 61, L. vardoense on 

 one side dravvs near to L. topldforme f. sjjhærica (ep. pi. II, fig. 

 12 — 13, 15), and is on the other side „almost fully resembling 

 small nodules of L. fornicatum f. suhsphærica, and partly even 

 f. dimorjjha." Cp. pi. II, fig. 1 — 11, 14, and Norw. Lithoth. pi. 

 10—12. There is a possibility of L. vardoense embracing two 

 different forms, but this question I cannot decide for the present, 

 because the fertile material in hånd is too scarce ; the larger number 

 of the specimens collected are sterile. When typically developed, 

 however, it corresponds to a small L. fornicatum, from which it 

 is distinguished only by developing bisporic sporangia. It shows 

 the same relation to L. tophiforme f. sphærica as small nodules 

 of L. fornicatum are bearing to L. soriferum f. glohosa. It is 

 sometimes rather dilficult to draw the line. Besides L. vardoense 

 is approaching to certain forms of L. glaciale, and on the other 

 hånd there are also forms of L. foryiicatum that are very nearly 

 connected with L. intermedium^), a species partly corresponding 

 to L. glaciale. 



Of late I have given particular consideration to the partition 

 of sporangia, and I have separated species as independent ones 

 only on this character, whereas my earlier opinion was that some 

 species are developing both bisporic and tetrasporic sporangia. 

 This limitation, however, has not been thoroughly carried out in 

 Rem. north. Lithoth. 2) Future investigations will show whether 

 such a limitation is right in all cases. 



The following species juxtaposited by twos are distinguished 

 from one another only by the partition of sporangia, — the former 

 of each group developing tetrasporic sporangia, the latter deve- 

 loping bisporic ones. 



L. nodulosum Fosl. — L. tusterense Fosl. 



L. lingeri Kjellm. — L. hreviaxe Fosl. 



1) I have got specimens referred to this species by Prof. Kjell man which 

 in my opinion belong to L fornicatum. 



2) Cp. Alg. Not. V (soon in press). 



