70 



Relation to other species. Among the species of Lithotham- 

 nion that I know L. clivergens exhibits the greatest resemblance 

 on the one side to L. fruticulosum f. curvirostra and on the other 

 side to L. coralloides, forming an intermediate species between 

 these tw r o. It is separated from the former especially by its more 

 spreading and less attenuating branches and larger conceptacles of 

 sporangia. Sometimes it much resembles certain forms of L. co- 

 ralloides in habit, particularly intermediate ones between f. norve- 

 gica and f. austvalis, but disinguishes itself from these by its in 

 general coarser branches and coarser structure, and also with re- 

 ference to the conceptacles of sporangia. Occasionally it also 

 reminds one of L. tophiforme in habit, but is separated by essen- 

 tial characteristics. 



Habitat. This species occurs on a depth of 3 — 5 fathom in 

 company with other species, as L. apiculatum and L. coralloides. 

 A few of the specimens collected in the former half of September 

 were provided with conceptacles of sporangia, most of which ap- 

 parently not fully developed. 



Occurrence. Hitherto only found at Skorpen in Kvasnangen, 

 north of Tromso, scattered and scarce. 



Lithothamnion flabellatum Rosenv. 



Gronl. Havalg. p. 772. 



f. Oranii Fosl. mscr. 



f. fronde initio affixa, crustam tenuissimam formante, tuberculis 

 vel ramis instructa, demum crusta evanida, fronde libera in fundo 

 jacente, decomposito subdichotome ramosa; ramis teretibus vel sub- 

 compressis, 2 mm. crassis, subattenuatis, apicibus plerumque ro- 

 tundatis; conceptaculis sporangiferis convexiusculis, parum promi- 

 nentibus, a superflcie visis diametro 350 p- ; sporangiis binas sporas 

 foventibus, 140—180 ;x longis, 45—60 /-* latis. 'Tab. 17, fig. 1—7, 

 tab. 22, fig. 1. 



f. Rosenvingii Fosl. mscr. 

 Descr. et Fig. Lithothamnion flabellatum Rosenv, 1. c. et fig. 1 — 2. 



Syn. Lithothamnion soriferum Rosenv. 1. c. p. 772; ex parte sec. spec. 



Remark on the species. The plant that Rosenvinge 1. c. 



