Clare Island Survey — Marine Algae. 15 Ho 



Habitat. — Sunny rock-pools, common ; rocks near low-water or shallow 

 sub-littoral region, rare. 



Season. — Spring to autumn. (Absent in winter ?) 



Distribution. — Ikeland, Co. Antrim (Giant's Causeway), Co. Donegal 

 (Bundoran), Co. Mayo (Achill, Clare Island, Boonah Point, Old Head, 

 Bellacragher Bay), Co. Galway (Dog's Bay), Co. Clare (Kilkee), Co. 

 Cork (Bantry Bay, one spec, in Herb. Univ. Cambiidge . 



Scotland, Ayrshire (Ballantrae, Herb. Ball, Dublin), Bute (Cumbrae, 

 Herb. Batters), Orkney (Herb. Harvey, Holmes), Iona (Herb. Greville). 

 Isle of Man (Port Erin, frequent in pools). 

 Exsice. — C. elongatum, Ag., Holmes, "Algae Eariores," no. 282. 

 Distinguished from C. tonientosum by its more robust fronds, and the very 

 much larger utricles which are often mucronate. The degree of mucronation 

 is variable in different specimens, and also in different parts of the same 

 specimen. In some individuals it is marked throughout the entire plant, in 

 others in the younger parts only, whilst in a few cases it is absent except in 

 the tips of the branches and in proliferations. In the latter mucronation is 

 often very marked indeed. 



The correct determination of this plant gives an additional species of 

 Codium to the continent of Europe. Entirely absent from England, and also, 

 as far as can be ascertained, from France and the Mediterranean, yet abundant 

 on parts of the west of Ireland and known to occur in the Isle of Man and 

 Scotland, it is to be regarded as one of the most interesting of the Clare Island 

 discoveries. Its distinct field-characters, and the fact that it is no recent 

 introduction, makes its previous non-recognition the more remarkable. 



Before discussing the question of the Irish plant, it may be well to refer 

 to C. mucronatuni as generally understood. J. Agardh founded the species in 

 1886. He distinguished three varieties (with no definite typical form) as 

 follows : — 



var. tasmanicum, Tasmania and Australia. 



var. Novae Zclandiae, Xew Zealand. 



var. californicum, California. 



The characteristic feature of the species was the mucronate utricle ; and the 

 varieties were based on the degree and form of mucronation. In addition to 

 the countries mentioned, the plant has since been recorded from South Africa, 

 Japan, and Cape Horn, but not from the North Atlantic. 1 There is a plentiful 

 supply in herbaria of both Australian and California!! material. An examination 



1 The Japanese and South African specimens require verification. 

 P2 



