15 120 Proceedings of the Roj/al Irish Academy. 



identification ; but tells me that Beinke's plant is synonymous with Stidyosiphon 

 atlriaticus. The branches in the latter alga, though usually regarded as 

 opposite, are frequently alternate. The distribution of S. (idriatieUs is 

 therefore much wider than was formerly thought, the plant being known not 

 only from the Mediterranean, but from Kiel (Eeinke), Cherbourg (Kuckuck, 

 1904, in lift.), and Clew Bay (1911). 



Dichosporangium Chordariae Wollny. 

 (Hedwigia, xxv, 1S86, pp. 127-130, tab. I, figs. 1-5, tab. ii, fig. 3.) 

 Though not previously detected in the British Isles, this minute endophyte 

 is probably frequent in the old fronds of Chordaria flagclliformis, as it is in 

 Heligoland. The Clare Island specimens were found in October, 1910, in 

 fronds that were also infested with Bulhocoleon. The plant is not related to 

 the original species of Dichosporangium (i.e. D. repeats = Myriofoichia repens 

 Kuck.) ; and there appears to be no reason why it should not be placed in 

 Streblonema. 



Sphacelaria britannica Sauv. 



Professor Sauvageau, who kindly looked over the material of Sphacelaria, 

 confirms the determination of this species, which is not uncommon on 

 boulders in caves and in similar shady spots. The plant was added to the list 

 of Irish algae by Battel's, who found it at Lambay. 



S. cirrhosa Ag. 



Exceedingly common in our area, extending from the shallow-littoral 

 i egion, through the littoral, and up to the highest rock-pools. It is usually 

 epiphytic ; but on semi-sheltered shores it forms an element in the sand- 

 association of the Rhodoelwrton floriduluin. In this condition it has often 

 been mistaken in the past for S. radieans. 



S. plumula Zan. 

 New to Ireland. A few specimens of this were dredged in 4 to 5 fathoms 

 in Clew Bay and at Eoundstone. 



MYRIONEMACEAE. 



The Myrionemaceae, as presented in our algological works, are in great 

 confusion, but it is hoped that the monograph, shortly to be published, will 

 bring about a measure of order. In the present report some of the results 

 are forestalled, alterations in nomenclature being made when necessary, and 

 an explanation given. 



