719 



The association almost exclusively consists of Rhodochorton Ro- 

 thii, yet Sphacelaria britannica, Ectocarpus liltoralis, Callithamnion, 

 etc. may be found intermingled ^vith it, and, epiphytically on 

 Rhodochorton, Pleurocapsa ameihijstea var. is often found in great 

 numbers. 



Rhodochorton Rothii can stand to be dried up to a considerable 

 degree, and may even be found apparently quite dry. It also very 

 well stands fresh water, not onlv rain, but also that of small 

 cataracts, growing sometimes at the very spot where the water falls 

 on the rock. 



The /?/zo(ioc/7or/o/7- association has been briefly described by 

 Simmons (p. 250), and Hansteen (p. 348) and Boye (p. 30) have 

 mentioned its occurrence on the west coast of Norway. 



The Bangia- Urospora- Association. 



On exposed coasts, prominent points and steep rocks are often 

 covered by a dense and matted reddish-brown vegetation, which in 

 dry condition shines almost like silk, unless it is curled up like 

 wool, as is often the case. It is Bangia fuscopnrpurea, an alga very 

 common on the coasts of the Faeroes. It is found like a dense 

 covering on the rocks, often at a very great height, 5 — 6 metres or 

 more, above the highest water mark. Consequently it can stand 

 being dried up for a long time, as well as being soaked with fresh- 

 water. 



Intermingled with Bangia, a luxuriant vegetation of Urospora 

 mirabilis is likewise often found; its growth is quite similar to that 

 oi Bangia; it also bears to be dried up, though perhaps to a lesser 

 extent. It forms a similar covering, on the rocks, only dark green. 

 They are both algae growing typically where the waves dash on 

 the coast (cf. Gran, 37, p. 9). Of these two algae, Bangia certainly 

 grows highest above the sea level, often forming here a pure Bangia- 

 facies; in much exposed places it extends far into the Porphyra- 

 association; Urospora however may also be found far above the 

 highest water mark. On Myggenaes Holm, for instance, this alga 

 was found at a height of at least 20 feet above the sea level, partly 

 as a subvegetation under and among larger algae, such as Fucus 

 in flatus f. disticha, Rhodymenia palmata, etc. 



Hansteen, who, strange to say, has not observed the Bangia- 

 association on the west coast of Norway, writes that it has been 

 found by Wille at Mandal. According to Wille, it formed an 



