15 12 Proceedings of the Royal Irish Academy . 



II. THE ALGAL VEGETATION. 



(1) Historical R£sum£ of Previous Work. 



As the present paper forms the first detailed account of the algal associa- 

 tions in any area in the British Isles, a general introductory sketch of the 

 subject maj be useful. 



Kjellmann's papers on the algal regions and formations of the Murman 

 Sea (77) and the Skager Rack (78), form the starting point of the modern 

 method of studying algal communities. Kjellmann divided the vegetation 

 into three " regions," and these he further divided into a number of " forma- 

 tions," which were characterized by a distinctive vegetative facies, due to the 

 predominance of one or more algae. 



The main outlines of Kjellmann's classification have been accepted by 

 subsequent writers, though of late years changes in terminology and great 

 elaboration have been noticeable. One of the earliest attempts to apply 

 Kjellmann's methods of study to other countries is contained in a paper by 

 Rattray ('85). The paper, which is a biological and ecological account of the 

 algae of the Firth of Forth, is seldom referred to, though it was apparently 

 the first and, until quite recently, the only one of the kind dealing with an 

 area in the British Isles. 



In other countries, however, this branch of ecology has received more 

 attention. The Norwegian algal vegetation has been studied by Hansteen 

 ('92), Gran ('93), Boye ('94-95), and Kylin (10), and an account of the 

 Faeroese algae was published by Simmons ('99). The Greenland marine algae 

 have been thoroughly studied by Eosenvinge, who, after giving two systematic 

 accounts, furnished a paper dealing with the algological communities ('99). 

 The marine algae of the Baltic have been investigated by Svedelius ('01), 

 who, in his " Osterjons Hafsalgflora," devotes a chapter to the algal regions 

 and formations found under the peculiar conditions presented in that area. 

 The question of defining the algal regions in the non-tidal Baltic had also 

 been dealt with by Eeinke ('89). The algae of the Faeroes have been 

 described a second time in the. " Botany of the Faeroes " ; and Borgesen's 

 treatise " The Algae Vegetation " ('05), which followed his systematic account, 

 is the most important contribution to this branch of algological literature. 

 Kylin, in his algal flora of the west coast of Sweden ('07), deals with associa- 

 tions and other ecological problems at some length. Joubin ('09) described 

 the marine communities at Boscoff, and published an elaborately coloured 

 vegetation-map. The map will be most useful to students working in the 

 locality ; but floristic and ecological data ai*e at present somewhat scanty for 



