Clare Island Survey — Marine Algae. 15 167 



to occur more or less frequently as far north as Norfolk. When Yorkshire is 

 reached, the four boreal species, Odonthalia, Rliodomela lycopodioidcs, Ptilota 

 plumosa, and Callithamnion arbuscula, become noticeable and are abundant from 

 this county northwards. The east of Scotland possesses a similar type of 

 flora, and additional northern forms appear (e.g. Stictyosiphon, Enthora). The 

 Orkney Islands, on the other hand, show a southern element, which is 

 doubtless present also in the Hebrides. Details as to the flora of the Hebrides 

 and the connexion with S.E. Scotland, N.W. and N.E. Ireland would be of 

 great interest. 



Foe roes.— The British and Faeroese floras have already been elaborately 

 compared by Borgesen ('05, pp. 784-788) ; and the Clare Island investigations 

 do not materially modify his statements. Borgesen naturally was most 

 concerned with the flora of Scotland and the Shetlands ; and in conclusion he 

 states that "the Faeroese algal flora must be regarded as a rather poor 

 selection of the algae of Scotland and the adjacent islands, as almost all the 

 Faeroese algae are found on the coasts of Scotland ; whereas Scotland, on the 

 other hand, has a very great number of species which are wanting at the 

 Faeroes. The greatest resemblance is between the Faeroese flora and that of 

 the Shetland Islands ; the Faeroes have a few, perhaps no more than six, 

 specially northern species, which will probably not be found in the Shetland 

 Islands." The six species referred to are Alaria Pylaii, Mhodophyllis 

 dichotoma, Halosaccion ramentacewm, Ptilota pectinata, Phodochorton 

 penicilliforme, and Lithothamnium laeve. Of these the Bhodochorton has 

 since been recorded as British (Batters, Journ. Bot., '06, p. 3) ; and a 

 somewhat doubtful record of L. laeve exists for Ireland. The first four, 

 however, could not easily be overlooked ; and it is very unlikely that they 

 extend as far south as the British Isles. With regard to Ireland, other 

 species might be added to Borgesen's list, as several which he assumes may be 

 found in the north of Scotland will hardly descend to Ulster ; and Fucus 

 infiatus, Enthord cristata, and Antithamnion floceosum, known on the east of 

 Scotland or Shetland, have never been found in Ireland. The curious over- 

 lapping of north and south in the algal flora of the west of Ireland consists, 

 as one would expect, in a continuous southern extension in the range of 

 certain boreal species rather than in the presence of isolated patches. 



France and, Spain.— The flora of France and the Bay of Biscay is of special 

 interest, and may be outlined here. The species found in Normandy and 

 Brittany are practically the same as those of Devon and Cornwall, though 

 doubtless in Brittany the southern element is present in greater quantity. 

 South of the Loire the flora undergoes a change ; and in the Biarritz and 

 Gu^thary. neighbourhood it possesses a decidedly southern faeies, Fucus and 



