727 



as subvegetation, CoralUna officinalis al the lowest part of the 

 association. All these species and a few others are rather frequently 

 foiind intermingled in this association. 



A Ca/W/jom/jzon-association probably similar to this Færoese 

 association has been found by Boye on the part of the west coast 

 of Norway which has been especially investigated by him. Judging 

 by his brief description it is probably quite similar to the Færoese 

 one. According to Hansteen (38, p. 346), the Callilhamnion-SLSSocia- 

 tion in the neighbourhood of Bergen is formed of Callithamnion 

 arhiisciila, whilst nothing is said oi Ceramiiim acanthonotam ; there is 

 however no reason to think that this species should be wanting there. 

 At Christianssund, I have found a vegetation corresponding exactly 

 with that of the Færoes, formed by the two characteristic algæ, 

 and growing on steep rocks facing the open sea. It grew almost 

 at the highest water mark. It has already been described by Ek- 

 man (17, p. 4) as being found in this place. Finally it may be sup- 

 posed that a vegetation well agreeing with that of the Færoes 

 may be found in Nordland (see Kleen 51, p. 9). 



I have also met with this association on exposed coasts in 

 Shetland, at Muckle Holm in Yell Sound. 



As before mentioned, Simmons (p. 250) calls this association 

 the Ceranirum-formation, or, with regard to Nordland, the Ceramium- 

 Callithanmion -formaiion. As that of the Færoes however corre- 

 sponds with that of Norway, I have not considered it justifiable to 

 change the name. 



The Rhodymenia- Association. 



A low, dense, dark, brownish-red vegetation, made up almost 

 exclusively of Rhodymenia palmata, is found on sloping rocks on 

 exposed coasts from a little below, or even a little above, high tide 

 mark, down to a little above lowest tide mark. It grows very 

 densely on the rocks, forming low tufts only a few inches high (see 

 plate XVI and XVII). It is mostly a narrow-lobed form, related to 

 f. sarniensis, which is found here, yet the typical form also occurs. 

 Generally this association is not intermingled with other larger algæ, 

 but a few Fucus inftatus f. disticha, Acrosiphonia albescens, etc. may 

 be met with. On the other band, there are many smaller epiphytes 

 on the thailus of Rhodymenia, among which Ectocarpus Htoralis, 

 E.tomentosus and E.fasciculatus, Myrionemaceæ, Chantransia virgatula, 

 C. seciindata and others should be pointed out. 



