694 



waves on exposed coasts than is Ihe case on sheltered coasts, where 

 the change of substance is likely to occur more slowly. 



From the composition of the algæ-vegelation one may tell at once 

 whether the coast on which they grow is exposed or sheltered, and if 

 we come from the open sea towards a sheltered place we may no- 

 tice how the algal vegetation changes in character. The change often 

 comes on gradually, but sometimes a sudden bend in the coast 

 may as suddenly change the character of the vegetation. 



This faet may often be observed, and by way of illustration I 

 may mention an investigation I made from the mouth to the head 

 of Kalbakfjord. I landed at short distances along the southern side 

 of this fjord , starting from Hvidenæs and noting the most impor- 

 tant species of algæ. Tides and current are liere scarcely perceptible. 



At Hvidenæs there is a perfect »open sea« algal vegetation. 

 Some small creeks with calcareous gravel excepted, the coast is 

 here mostlj' steep, almost vertical, and as is usual in such piaces 

 is covered from low water mark downwards by a dense Alaria- 

 vegetation, and above it by the Balamis-he\\., which supports several 

 of the smaller red and brown algæ, e. g. Ceramium acanthonotum, 

 Polysiphonia urceolata, Callithamnion arbiisciila, Ectocarpiis litoralis, 

 etc. The littoral vegetation is however rather scanty on these ver- 

 tical cliffs, which is probably due to the faet, that the sea is often 

 relatively calm at this place, especially in summer, Nolso as well 

 as Ostero yielding it some shelter. A little west of Hvidenæs (the 

 place is marked 1 on the accompanjdng sketch, Fig. 151) the following 

 species were the most prominent, passing upwards from the sea 

 level: Alaria esciilenta, Himanthalia lorea, Gigartina mamillosa, Cera- 

 mium acanthonotum, Callithamnion arbuscula, Scijtosiphon lomentarius 

 in small numbers in shallow pools, Fucus spiralis f. nana and Por- 

 phijra umbilicalis; as may be seen, exactly the vegetation of exposed 

 coasts. A little farther on, at 2, where the shore is likewise steep, 

 but with scattered rocks fallen from the overhanging clifTs, almost 

 the same algæ were found: Alaria esculenta, Himanthalia lorea, Gi- 

 gartina mamillosa, Fucus spiralis f. nana, Porphijra, Enteromorpha 

 intestinalis var. genuina and var. micrococca. We thus have still the 

 algal vegetation of exposed coasts, which was also found at 8, al- 

 though the somewhat larger forms of Fucus indicate a somewhat 

 more sheltered spot, viz. : Alaria esculenta and Laminaria digitata, 

 Himanthalia, Polysiphonia urceoluta, Gigartina mamillosa, Ceramium 

 acanthonotum and C. rubrum, Callithamnion arbuscula, rather large 



