732 



Mingled witli the characteristic algae, we find e. g. Cerawiiim ru- 

 briim, Cladophora rupestris, and very rarely Cladostephiis spongiosus. 

 Corallina is usually absent in this association, as the dense growth 

 of both species leaves no room for a subvegetation. 



Tliis association, which is very common in the Faeroes, lias 

 not been described by Simmons, nor by any Norwegian investi- 

 gator. It is however undoubtedly closely connected witli Han- 

 steen's »Broget-pelagiske-formation« (38, p. 348) and partly related 

 to Bo3^e's »Gigartinaformation« (6, p. 22 — 23). 



The Gigartina- Association. 



Somewliat above the lowest water mark, the lieight varying ac- 

 cording to the exposure of the localit}^ a vegetation of Gigartina nia- 

 mitlosa (see plate XVIII and XXI), often dense and up to 6 inches high, 

 is found in the Co/'rt//z/?o-formation. This association often extends 

 far horizontally, and on almost horizontal rocks, found within the 

 level of this association, it is often widely distributed (see plate XVIII). 

 Vertically it usually reaches only to a height of one or two feet; 

 the height being the greatest on specially exposed coasts. 



Epiphytes common on Gigartina are: Chantransia virgatuta, very 

 often forming a dense, velvety covering on the stalky part of the 

 thallus, and Dermatolithon macrocarpum f. fairoensis which grows 

 on it in smaller or larger pale pink incrustations. Ceraminm ru- 

 hram, Cliondrus crispns, Polysiphonia urceolata, Acrosiphonia albe- 

 scens^ and frequently some younger or older plants of Himanthalia 

 lorea, besides Corallina officinalis, are found mingled with Gigartina. 

 But generally these algae are only few in numbers, or they may be 

 totally wanting, so that the dark reddish-brown colour of the Gigar- 

 tina predominates. Gigartina mamillosa grows luxuriantly in the 

 most exposed places. Its tough, cartilaginous character probably 

 makes it well fitted for resisting the surf. It is hardly exposed to 

 any drying process, as it generally grows at the lower part of the 

 littoral region. 



According to Hansteen (38, p. 348), and Boye (6, p. 22), a si- 

 milar Gz^ar///?a-association is found along the west coast of Nor- 

 way. It seems to difier from the Faeroese association only in its 

 colour. Boye writes: »It (the formation) is easily distinguishable 

 at a long distance as a light yellowish green belt, immediately above 

 the lowest water mark, because the algae inviduals are faded by the 



