15 168 Proceedings of the Rot/al Irish Academy. 



Ascophyllum are practically absent from Biarritz, and such plants as 

 SpatJioglossum Solierii and Liagora viscida are of frequent occurrence. 

 On the north coast of Spain these southern species cease to flourish ; 

 and a vegetation of the Brittany type re-appears. At Cape Ortegal 

 the flora changes again; and, by the advent of such algae as Phi/Maria 

 purpurascens and Laminaria pallida, it receives a stamp which is 

 characteristic of Cadiz and Morocco (see Sauvageau, '97). There appears 

 to be no element in the Irish flora which is specially characteristic of 

 the Spanish peninsula. Many species are common to both countries ; but 

 these for the most part extend right up the coast of France, and are also 

 to be met with on both sides of the English Channel. The Biarritz neigh- 

 bourhood is peculiar in possessing a flora of particularly austral type. 



Neither is there any evidence of a S.W. France or Mediterranean 

 element, such as is represented amongst flowering-plants by Dabeocia and 

 Erica mediterranca. The two Mediterranean algae for which the west of 

 Ireland was specially noted were both wrongly named ; and a third less 

 familiar species, with the same geographical distribution, has had to be struck 

 off the list. The record of Godium elongatum (a native of the South of France 

 and North Africa) was an error for C. mueronatum; Lithophyllvm dentatum (a 

 species not known outside the Mediterranean) must be replaced by 

 L. incrustans var. subdichotomwm [teste Lemoine, p. 146); and Peyss&nnelia rubra, 

 though still a puzzle, was certainly an erroneous determination. The last- 

 named has been recorded from many warm-temperate and tropical regions, 

 often incorrectly. It was originally described from the Ionian Islands, and 

 in the British Isles was supposed to occur at Eoundstone and Plymouth. 

 The species of the genus are singularly difficult to differentiate ; but whatever 

 the Irish plant may be, it is clear from an examination of the type specimens 

 that it is not P. rubra. On the other hand, Bornetia sccundiflora, which is 

 abundant in the Mediterranean, and found sparingly in Brittany, Devon, and 

 Cornwall, and more frequently in west France, may be added as a rare 

 plant to the west-coast list. The majority of the southern species listed for 

 Clare Island appear to have their headquarters in S.W. England, W. France, 

 and N. Spain, rather than in southern Europe. 



4. Origin of the Flora. 



The origin of the algal flora at present found in the Survey area is a 

 subject as to which we have very little to guide us. The source of the Clare 

 Island flora as distinct from the mainland presents, of course, no difficulty, 

 whatever view be taken as to the date and manner of the formation of the 

 island. But any theory as to the origin of the marine flora of the west of 



