15 166 Proceedings of the Royal Irish Academy . 



mere list of species found floating, either of their own accord, or entangled 

 with debris, would be of interest, and could be easily compiled by those who 

 spend much time in dredging, tow-netting, etc. The algal growths on the 

 bottoms of both large and small vessels present, moreover, an almost unworked 

 field. 



3. Comparison with other Areas. 



East Ireland. — A comparison of the floristic features of the east and west 

 of Ireland does not reveal so great a contrast as was expected. No special 

 account of the east-coast flora has been published, nor have I personally examined 

 any part of the shore, except the extreme north. Adams ('OS, annotated copy) 

 lists most of the Clare Island austral species for Leinster, and a considerable 

 number for Ulster also. There are, however, ten well-known and conspicuous 

 algae which have not yet been recorded for the east coast, but most of these 

 woidd probably be found in Leinster if carefully searched for. S.E. Leinster is 

 similar, as to its flora, to Minister ; and Ulster has a surprising number of 

 southern species, Belfast and Larne Loughs being at one time famous for 

 Nitophylla and other seaweeds which occur chiefly in the southern counties. 

 At the same time, it would be advisable to confirm such records as Bifucaria, 

 Gallithamnion tetricum, and Schizymenia Dubyi. The real difference between 

 the east and west coast lies doubtless in the proportion of southern vegetation 

 present ; plants which are common or frequent in Mayo and Galway being 

 probably rare or very rare in Co. Dublin. The luxuriant growth displayed by 

 such species as Loni.entaria clavellosa and Dasya arbusctda is also a characteristic 

 feature of the west-coast vegetation. 



England and Scot/and. — "With regard to England, as already shown, the 

 Clare Island flora resembles that of Devon and Cornwall, but in England the 

 boreal element (represented by Collithamnion arbuscula, and Ptilota plumosa) 

 is wanting, as are also several other northern species. Codium mucronatum is 

 likewise entirely absent. Such plants as Acrothrix and Stictyosiphon adriaticus, 

 known at present in the British Isles only from Ireland, will probably be found 

 in England when our south-coast bays have been more thoroughly explored 

 by dredging. On the other hand, a few well-known and conspicuous species, 

 more or less frequent in Devon and Cornwall, have not been found in Ireland. 

 Ine most noteworthy amongst these are Punctaria crispata, Gracdaria 

 compressa, Grateloupia filicina, G. dichotoma, and Spyridia filamentosa, the last- 

 named being locally abundant in Great Britain, and extending from Sussex to 

 Anglesea. There are also other species, but these are of very rare occurrence. 

 The east coast of England is comparatively poor; more than two-thirds of the 

 species listed on p. 162 are entirely absent ; the remainder have been reported 



