722 



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

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

 both species growing together 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 inches long, 

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

 only by removing them that we discover the red subvegelation 

 of Hildenbrandia whicli is common here, togetlier with tlie inter- 

 mingled lichens. 



Forms o^ Ectocarpiis littoralis, sipec'ies of Ulothrix, besides Elachi- 

 sta fucicola, and a few others frequently grow epiphytically on the 

 Fucus-plants. Among the latter, Porphyra umbilicalis, Enteromorpha 

 intestinalis and other littoral algae are often met with. 



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

 racteristic of the most exposed places (see fig. 153), the Fucus-plants 

 gradually become larger as the locality becomes more sheltered (see 

 plate X!V), 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 growling uppermost, at or above 

 the highest water mark, whilst large, w^ell- 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 

 Gliversn?es, on the east of Stromo (see plate XIV), a locality where 

 Nolso really affords some shelter, but w^hich must be considered 

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

 the Fucu5- vegetation of exposed coasts to that characteristic of a 

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

 exposed coasts gradually become larger, but they are joined by 

 Pelvetia canaliciilata , Ascophylhim nodosum and Fiiciis uesiculosiis. 

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

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

 ing abundantly for instance on rocks on the west 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 growls is, howTver, always some- 

 w'hat sheltered. It is, for instance, never found on rocks facing 

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

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

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

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



