824 



there abundantly, if a postglacial land-bridge had existed, by aid of 

 which it might easily have macle the passage. 



Several sublittoral algae e. g. Chwtopteris plumosa, Phyllophora 

 rubens, Dilsea ediilis, Brongniartella byssoides, etc. are also wanting 

 at the Faeroes, though they are more or less frequent in the sur- 

 rounding seas. 



When everything is taken into account, the algae-flora from the 

 deeper sea has perhaps had the greatest difficulty in reaching the 

 islands. This perhaps explains, why some sublittoral algae which 

 might reasonably be expected to grow at the Faeroes are not found 

 there. The sublittoral algae which grow deep down are probably 

 the least fitted for floating a lon§ time, and as to their adhering 

 to algae from the littoral region or to floating timber as a means 

 of transport, this likewise seems to occur only rarely. On the other 

 hand we know but little about the first stages of development of 

 many of these algae. We especially want to know whether the 

 different reproductive organs are able to float for a long time in 

 the sea apart from the mother-plant. They may possibly be carried 

 far about as plankton ^ Finally if the algae spores cannot lloat 

 far either l)y themselves or by the agency of the sea currents, it 

 is however probable, that they can stick to the mucilage of larger 

 algae, or to the mucus of fishes, and thus be carried off. 



It is hardly probable, that any of the sublittoral algae have 

 been able to survive the glacial period, according to Geikie^. He 



^ In connection with this it may be pointed out, that the late Prof. CI eve, the 

 well-known Swedish plankton-investigator, thinks it probable that algie-spores can 

 be carried about by the agenc}'^ of marine currents. He has even expressed the opi- 

 nion , that the stunted forms of algae from the Polar Sea met with in the Baltic 

 can have been carried there together with Arctic plankton (see Hotaniska Notiser, 

 1898, p. 269). If it is so, the short distance from the English coast to the Fseroes 

 is nothing by comparison. It should however be observed that these forms of 

 algae in the Baltic must rather be considered as »relicts« as pointed out by Sve- 

 delius (Studier ofver Ostersjons Hafsalgflora, p. 68 — 69). 



A remark by Oltmanns should also be mentioned here. In a paper 2>Notizen 

 iiber die Cultur- und Lebensbedingungen der Meeresalgen« (Flora 1895), after having 

 emphasized the necessitj^ or at least the desirability of having sterilised sea water 

 for culture-experiments, he writes: »Die Steriliserung ist aber auch besonders dann 

 unerlassig, wenn man kleine Ectocarpeen einigermassen rein cultiviren will, well 

 das Seewasser fast zu jeder Jahreszeit und an jedem Ort eine recht 

 e r h e b 1 i c h e A n z a h 1 von S c h w a r m s p o r e n der v e r s c h i e d e n s t e n Species 

 enthalt, welche alle neben den ausgesaten Formen keimen wurden.« 

 (The emphasis is mine.) 



^ Geikie, James, Prehistoric Europe. A Geological Sketch. London 1881, 

 p. 663. 



