36 THE JOURNAL OF BOTANY 



Gallitliamnion arbuscula is a boreal alga. It is found in Norway, 

 the Faeroes, Scotland and Ireland, and is abundant in the Glare 

 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 plwnosa is also a northern 

 species. Found in Iceland, Nova Zemblya, and Spitzbergen, it 

 descends 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 Lami- 

 naria Cloustoni and washed ashore in company with such south- 

 ern plants as Taonia and Gallymenia reniformis. It is supposed 

 to occur right round Ireland. With regard to these two species 

 it was pointed out (1. c. p. 170) that ecological factors appeared 

 more likely to explain their absence on the south and west coasts 

 of Great Britain than unfavourable currents or lack of spores. 

 Both require an open rocky coast, and the scarcity of such ground 

 south of Yorkshire may have limited their range in the North 

 Sea, and prevented their access to the Straits of Dover. But on 

 the west coast this explanation does not hold, rocky ground being 

 plentiful both in north and south Wales. The third species, 

 Godium viucronatum (first correctly identified during the Glare 

 Island Survey), is a much more remarkable plant. Frequent in 

 Australia and New Zealand, and almost identical with the form 

 known as Nova Zelandice, it is in Europe only known from the 

 British Isles. Though long overlooked, it can happily be recog- 

 nised with certainty in the herbarium, and its distribution was 

 carefully worked out for the Glare Island Eeport. It occurs in 

 Scotland from Orkney to Bute, and in the north of Ireland from 

 Antrim to Donegal, and from thence southward to Bantry Bay. 

 On Clare Island it is plentiful and conspicuous. In the Irish 

 Channel it occurs on the Isle of Man, but is absent (as far as is 

 known) from the east of Ireland, from England, and from the 

 rest of Europe ; also from the Atlantic coasts of North America. 

 The plant can hardly have been introduced to Ireland, since it 

 has existed in Bantry Bay for over a century. A special look-out 

 for this alga should be kept, as any data that would throw light 

 on its isolated position in Europe would be highly valuable. 



1. Gardigan Bay. — The two regions investigated were those 

 of Barmouth and Aberystwyth, advantage being taken of the 

 British Mycological Society's meeting at Dolgelly in May 1913 to 

 examine the coast-line in the vicinity. The rocks are slaty, Cam- 

 brian and Silurian respectively. In neither locality did the ground 

 appear suitable for the algse sought for. The shore is flat, and 

 does not possess steep, clean, exposed rocks, the well-known 

 habitat for C. arbuscula. No specimens of L. Gloustoni (the 

 usual host of P. i^lumosa) were noted, but it is possible, and 

 indeed likely, that that plant occurs in deeper water. Clean rock- 

 pools, of the type in which Godium viucronatum flourishes, were 

 also absent. At Aberystwyth a large amount of angular gravel is 

 present (probably derived from glacial drift), and the injurious 



