54 



The Irish Naturalist. 



March, 



SOME MARINE ALGAE OF COUNTY CORK. 



BY BLANCHE E. DUKE, B.SC, A. R. CSC. I. 



The Marine Algae which I propose to deal with are the 

 rarer Irish species in the Herbarium of University College, 

 Cork. 



Between the years 1878 and 191 1 there were no ad- 

 ditions to the collection, but recently some rather interesting 

 species have been added from Courtmacsherry Bay and 

 Cork Harbour. Of these, two of the most noteworthy are 

 C allithamnion arhuscula and Ptilota plumosa. 



" C allithamnion arhuscula is a boreal alga. It is found 

 in Norway, the Faeroes, Scotland, and Ireland, and is 

 abundant in the Clare Island district, forming a band on 

 rather steep exposed rocks. In the much colder waters 

 of the North Sea it does not occur south of Yorkshire, and 

 on our west coast it was known to descend to Ayrshire 

 and Isle of Man. Ptilota plumosa is also a northern species. 

 Found in Iceland, Nova Zemblya, and Spitzbergen, it de- 

 scends as far as Yorkshire on our east coast, and had been 

 recorded from North Wales and the Isle of Man on the west. 

 On Clare Island it is plentiful, being attached to the stipes 

 of Laminaria Cloustoni and washed ashore in company 

 with such southern plants as Taonia and Callymenia reni- 

 formis.'''' '* Both are supposed to occur in the South of 

 Ireland, but this requires confirmation." 



The quotations are taken from Mr. A. D. Cotton's paper 

 on The Distribution of certain British Algae," Journ. Bat., 

 Feb., 1914. At that time he had not been able to see any 

 specimens and some so labelled were wrongly named. The 

 statement that they do occur can no longer be doubted, 

 both having been collected by me in Courtmacsherry Bay 

 last August. 



This bay is very much sheltered on the western side, but 

 on the eastern side, from Garrettstown to the Old Head of 

 Kinsale, is decidedly exposed. It was at the very extremity 

 of the '* Old Head," near the lighthouse that C allithamnion 

 arhuscula was found. Here the cliffs are very precipitous. 



