280 Marine Algce of Bemvick-on-Tweed. 



Sphacelaria radicans (Dillw.) Harv. 



in Hook., Br. Fl. n., p. 324.— Conferva radicans, Dillw., 

 Suppl. p. 57, t. 0. 



F. TYPICA. 



Conferva radicans, Dillw., I.e. ; E.B. t. 2138. 

 Filaments erect, tufted or loosely csespitose (never felted) 

 rhizoidal filaments few, branches scattered, irregularly placed, 

 appressed. More than two rows of longitudinal cells in the 

 width of a filament. 



Fig. Sphacelaria radicans, Harv., Phyc. Brit. pi. 189. 



,, olivacea v. radicans, Pringsheim, Sphacel., pis. 9, 10. 



Exsicc. ,, ,, radicans, Wyatt, Alg. Danm., no. 210 ; Holmes, 



Alg. Brit. Ear., no. 96. 

 Hah. In shallow, exposed, sandy pools between tide-marks. Common. 

 All the year. Berwick Bay. Bnrnmouth. Holy Island, and 

 elsewhere along the coast. 



F. OLIVACEA {DilllO.) 



Conferva olivacea, Dillw., Suppl., p. 57, t. C. 

 Filaments, decumbent, felted below owing to the interlacing 

 of the branches, forming indefinitely expanded turfs, rhizoidal 

 filaments numerous, branches irregularly placed, given off at 

 wide angles, primary and secondary branches nearly similar. 

 Usually only two rows of longitudinal cells in the width of a 

 filament. 



Exsicc. Sphacelaria radicans, f. olivacea, Holmes, Alg - . Brit. Bar., no. 



9(5 (bis.) 

 Fig. Conferva olivacea, Dillw., I.e. 



Sphacelaria olivacea, Traill, Trans. Bot. Soc. Edin., vol. xvii., 

 PI. ir. ; E.B. t. 2172. 

 Hah. On the walls of caves, and' in the shade of overhanging 

 rocks near high- water mark. Not nncommon. Fruit Dec. — 

 March. Sharper Head, Coves, Holy Island, Burnmouth, etc. 

 A common species on our coast, which, though offering two 

 marked forms, cannot, as it seems to me, be specifically divided. 

 What I have called forma typica is, I believe, the plant described 

 by Dillwyn under the name Conferva radicans and consequently 

 entitled to be considered the type of the species, the form of 

 the same species subsequently described by him under the name 

 Conferva olivacea being regarded as a variety of it. 



The typical form grows in exposed sandy pools between tide- 

 marks, many plants growing side by side and forming indefinite 



