15 162 



Proceedings of the Royal Irinli Academy. 



scarcity of records. The fact thai the Survey has added about 250 species to 

 Connaught, and over LOO species and varieties to [reland, shows how little we 

 really know of the distribution of algae. The south-east of Ireland needs 

 special attention ; also south-west Wales, north Cornwall, and the Scilly Isles. 

 Borgesen has pointed out how badly the Shetland algae are in need of 

 re-investigation ('05, p. 787 ; see also '03) ; and the same applies with equal 

 force to north-west Scotland. For Donegal and the coast-line generally 

 between Achill and Portrush there is hardly a record; and yet it is along this 

 coast that the southern species disappear and the northern forms, such as 

 Odonthalia dentata, Porphyra miniata, and Monostroma fuacum, begin to show. 

 With regard to France and Spain, although we have good French handbooks, 

 additions to the Mora may still be made ; and were it not for Sauvageau's two 

 valuable lists ('97), which are admittedly preliminary, we should have 

 practically no reliable data for the north of Spain. 



For the above reasons I have not attempted to classify the whole flora 

 into definite phytogeographic groups. We may, however, recognize certain 

 well-marked elements, and by means of these attempt to analyse it. 



(a) Southern Element. — Of the species which have a markedly southern 

 distribution, the following are among the most noticeable : — 



Cladophora prolifera. 

 Codium adhaerens. 

 Mesogloia lanosa. 

 M. Griffithsiana. 

 Petrospongium Berkeleyi. 

 Cutleria multifida. 

 Bifurcaria tuberculata. 

 Cystoseira ericoides. 

 C. granulata. 

 Taonia atomaria. 

 Dictyopteris membranacea. 

 Nemalion elminthoides. 

 Callymenia reniformis. 

 Bonnemaisonia hamifera. 



Bostrychia scorpioides. 

 Chondria tenuissima. 

 Polysiphonia subulifera. 

 P. furcellata. 

 Dasya corymbosa. 

 Spondylothamnion multifidum. 

 Halurus equisetifolius. 

 Monospora pedicellata. 

 Bornetia secundirlora. 

 Callithamnion granulatum. 

 C. tripinnatum. 

 Compsothamnion thuyoides. 

 Schizymenia Dubyi. 

 Corallina squamata. 



We may mention also eight species which were not found during the 

 Survey, but are known to occur in S.W. Ireland : — 



Asperococcus compressus. Nitophyllum Gmelini. 



Helminthocladia purpurea. Pterosiphonia complanata, 



Gigartina acicularis. Dasya ocellata. 



Nitophyllum Hilliae. Callithamnion tetricum. 



