Marine Alyw of Berwich-on-Tweed. 335 



A small species which might, at first sight, be mistaken for a 

 small form of Rhodymenia niavensis, from which it differs in the 

 disposition of the cystocarps, which are entirely immersed in 

 the tissue of special marginal leaflets, whereas in Rhodymenia 

 nicceensn they are scattered, and sessile either on the margin, or 

 on the blade itself, in which case they are prominent on one side 

 only of the frond. From Phyllophora palmettoides it is distinguished 

 by the absence of the widely expanded radical disc. 



The present species is very small, seldom being more than one 

 or one and a half centimetres high. The filiform sterns are 

 either simple or branched, and expand into oblong or wedge- 

 shaped laininae which are either simple or slightly forked, some- 

 times more or less irregular in outline, and usually fringed with 

 minute, almost colourless leaflets. The cystocarps are entirely 

 immersed in special marginal leaflets, the spores numerous and 

 arranged in irregular masses, the nematheeia are as yet unknown. 



The plant grows under overhanging ledges of rock, usually 

 very much in the shade, and often in such narrow crevices that 

 it is difficult to see it, and still more difficult to reach it. The 

 fronds grow singly and are sparsely scattered on the rock, often 

 mixed with sponges, &c. 



The species is named in honour of its discoverer, Mr G. W. 

 Traill of E linburgh, who has done so much to increase our 

 knowledge of the marine Algae of the Firth of Forth. 



CYSTOCLONIUM, Kt%. 



Cystoclonium purpurascens (Huds.) Etz. 



Phyc. Gen., p. 404.— Fucus purpurascens, Uuds., Fl. Angl., 

 p. 589. 

 Descr. Hypnea purpurascens, Harv., Phyc. Brit. 

 Fig. „ „ Harv., I.e. pi. 116. 



Exsicc. Cystoclonium „ Crouan, Alg. Finist., no. 198 ; Le Jo!., 



Alg. Mar. Cherb., no. 226. 

 Gigartina purpurascens, Wyatt, Alg. Damn., no. 74. 

 Syn. „ ,, Lamowr., Ess., p. 136 ; Lyngb., Hydr. 



Dan., p. 46, t. 12 ; Duly, Bot. Gall, n., p. 952 ; Johnston, Fl. 

 Berw. n., p. 234. 

 Spaerococcus purpurascens, Ag., Spec. Alg. i., p. 318 ; ^.,Syst., 236. 

 Gracilaria purpurascens, Grev., Alg. Brit., p. 122. 

 Cystoclonium purpurascens, J. Ag., Spec. Alg. n., p. 307 ; Id., 

 Epicr., p. 239 ; Ktz., Spec. Alg., p. 756. 

 Hab. In pools near low-water mark. Fruit June — Oct. Not un- 

 common. Berwick Bay, Bnrnmonth, Holy TsJanrl. 



