Marine Al;jce of Berwick-on-Tiveed. 271 



Cliordaria JlagelUformis, and Prof. Agardh considers that it is 

 only an abnormal state of that species in which the peripheral 

 layer of horizontal filaments have not been developed. The 

 present species is always excessively branched, the branches 

 beset with long alternate or opposite secondary branches which 

 are once or twice re-branched in a similar manner, whereas the 

 fronds of Cliordaria flagelliformis are subsimple furnished with 

 long branches which are either naked or furnished with a few 

 simple ramuli. 



Dictyosiphon mesogloia, Aresch. 

 Obs. Phyc. 3, p. 33. 

 Descr. Dictyosiphon mesogloia, Aresch., I.e. 

 Exsicc. ,, ,, Aresch., Alg. Scand. Exsice., no. 106 ; 



Holmes, Alg. Brit. Rar., no. 6. 

 Hob. In shallow sandy pools between tide-marks. May— Sept. Eare. 

 By the side of the posts which mark the road between Fenham 

 Flats and Holy Island. 

 A rare and interesting species first noticed within our limits 

 by Mr Holmes in the summer of 1884. The fronds are much 

 thicker than those of any other British species of Dictyosiphon, 

 and as Mr Holmes has remarked the plant when seen growing 

 might be mistaken for Castagnea virescens, from which it is only 

 distinguishable by the acute apices of the ramuli. 



The somewhat clumsy fronds, which are hollow below, are 

 very irregularly branched, the branches given off at wide angles 

 and furnished with short ramuli with acute apices. The whole 

 plant is very lubricous, but not gelatinous as is the case with 

 Castagnea and Mesogloia. 



STICTYOSIPHON, Ktz. (1843). 



Pldaospora, Aresch (1873) sec. like. 



Stktyosiphon tortilis (Eupr.) Rice. 



Algenflora derweslichen Ostsee, p. 54. — Scytosiphon tortilis, 

 Rupr., Alg. Och., p. 373. 

 Descr. Phloeospora tortilis, Aresch, Bot. Not. 1876, p. 34. 

 Fig. „ „ Kjellm., Spetsb. Thall. n., t, i., fig. 21. 



E< sice. „ ,, Areseh, Alg. Scand. exs., no. 413; Holmes, 



Alg. Brit. Rar., no. 20, 



