722 



Vaag's Ejde, whilst Fiiciis spiralis only was found less exposed in 

 the latter place. I mvist nevertheless point out, that I have found 

 both species growing togetlier on the west coast of Lille Dimon, 

 which must also be considered a particularly exposed place. 



The F«c»s-planls hang in small, dense tufts, a few indies long, 

 down the sloping rocks, often covering them so closely, that it is 

 only by removing them that we discover the red subvegetation 

 of Hildenbrandia which is common here, together with the inter- 

 mingled lichens. 



Forms of Hctocarpiis littoralis, s\^ecies of Ulothrix, besides Elachi- 

 sta fiicicola, and a few others frequcntly grow epiphytically on the 

 F«c«s-plants. Among the latter, Porphyra umhilicalis, Enteromorpha 

 intestinalis and other littoral algæ are often met v^ith. 



Whilst these small specimens, only a few inches high, are cha- 

 racteristic of the most exposed piaces (see fig. 153), the Fncns-plants 

 gradually bccome larger as the localily becomes more sheltered (see 

 plate XIV), and the most regular gradations may then be found, 

 from the typical large form, f. edentata (fig. 158), to the dwarf form, 

 f. disticha. Sometimes they may even be found growing in the 

 same locality, the smaller form still growing uppermost, at or above 

 the highest water mark, whilst large, well-developed specimens be- 

 longing to the main form grow at the lowest part of the beach. 



This may easily be observed along the coast, between Arge and 

 Glivers«æs, on the east of Stromo (see plate XIV), a locality where 

 Nolso really affords some shelter, but which must be considered 

 rather exposed. A very easy transition may be found here from 

 the FwcHS- vegetation of exposed coasts to that characteristic of a 

 sheltered coast, as not only the two species of Fucus growing on 

 exposed coasts gradually become larger, but they are joined by 

 Pelvetia canaliciilata , Ascophijlhim nodosum and Fucus uesiculosus, 

 I have observed that these three algæ appear in the order I have 

 named them. Pelvetia may be found in rather exposed piaces, grow- 

 ing abundantly for instance on rocks on the w^est coast of Sydero, 

 at Vaag's Ejde, at a height of about 5 metres above the sea-level 

 (see fig. 154). The place w^here it grows is, however, always some- 

 what sheltered. It is, for inslance, never found on rocks facing 

 the open sea, but on rocks facing the land, or at least in piaces 

 sufficiently sheltered from the strengest surf. At Vaag's Ejde, a very 

 exposed place, Ascophyllum nodosum is also found on the most shel- 

 tered, inmost rocks, but I have not seen Fucus vesiculosus there. 



