I899-] 175 



A VISIT TO ROUNDSTONE IN APRII,. 



BY M. FOSUE. 



Since the publication of Harvey's Phycologia Britannica, about 

 fifty years ago, Roundstone, on the west coast of Ireland, has 

 been well known for marine botany. Several of the rarer and 

 more interesting of British seaweeds are found in this locality, 

 and some have only been found here up to the present time. 

 Among the latter are Lithothamnion agariciforme and L. 

 fasciculatum, Harv. 



Working with calcareous algae for some years, it has been of 

 great interest to me to understand clearly the Lithothamnia 

 described by Harvey. For instance, L.fasciculatum is one 

 of the Corallines very differently interpreted by different 

 writers. In fact, two authors, writing about this alga, have 

 understood different species. So also as regards L. agari- 

 cifo7ine, as well as L. calcareum, the latter quoted by Harvey 

 from different parts of the Irish and British coasts. This mis- 

 understanding is due to the fact that Harvey's type specimens 

 of this group of algae are lost, and the descriptions and figures 

 of sterile specimens are all that can be relied on in arriving at 

 what was understood. 



The above Roundstone species have, according to Harvey, 

 been collected by M'Calla. Apparently a small part of 

 M'Calla's collection, now in the Science and Art Museum 

 Herbarium, Dublin, labelled L. agai'iciformc, is not to be 

 considered as authentic, since the labels, according to Prof. 

 T. Johnson, have been re-written some time before they were 

 acquired by the Museum. They do not quite correspond with 

 Harvey's figure nor his description. On the other hand, some 

 of them may perhaps belong to the same species, but un- 

 fortunately, so far as hitherto examined, they are sterile and 

 not suitable for accurate determination of the species. 



Therefore, I took the opportunity of visiting Roundstone 

 early in the year, as many of the calcareous algae do not 

 appear to possess fruit in summer. Professor T. Johnson 

 greatly facilitated my object by placing at my disposal his 

 advice and suggestions gained from a previous visit, as well as 

 apparatus, dredges, &c, and has given me the opportunity of 



