288 Marine Algce of Benvick-on-Tweed. 



Ealfsia clavata (Carm.) Crouan. 



Florule du Finist., p. 166. — Linckia clavata, Carm., Alg. App. 

 ined cum ic. 

 Descr. Ralfsia clavata, Farloiv, Mar. Alg. New Eng., p. 88. 

 Fi<j. Stragularia adherens, Stromfelt, Algveg. Islands Kuster. pi. n., fig. 



13, 14, 15. 

 Exsicc. Ralfsia clavata, Crouan, Alg. Mar. Finist. 56 (pro parte.)* 



Holmes, Alg. Brit. Rar., no. 90. 

 Syn. Myrionema clavatnm, Harv. in Hook., Br. Fl. vol. n., p. 391 ; 

 Harv., Phyc. Brit. pi. 348 ; J. 67. Ag., Spec. Alg. i., p. 50. 

 Myrionema Henschii, Casp., Seealgen v. Neukuhren Schriften d. 

 Phys. okon Ges. zu Konigsberg xn., 1871, p. 142 (Fide Hauck); 

 Hauck, Meeresalgen von Deutschland, p. 322 (ex ipso Hauck.) 

 Stragularia adherens, Stromfelt. Meeresalg Isl., p. 173 ; Id. Om 

 Algvegetationen vid Islands Kuster., p. 49, t. n., fig. 13-15 (ex 

 ipso Stromfelt). 

 Hah. On rocks and stones from half-tide level to low-water mark. 

 Fruit Jan. — March. Rare. Berwick Bay, Sharper Head, 

 Scremerston. 

 A small species forming closely adherent crusts on rocks and 

 stones between tide-marks. The fronds are at first orbicular, 

 but soon become indefinite in outline, and as is the case with 

 Ralfsia verrucosa and Ralfsia spongiocarpa the central part often 

 dies away, in winter, leaving the circumference in the form of a 

 circular band. The unilocular sporangia are large, pyriform in 

 shape, and usually only partially filled by the sporal mass, the 

 upper portion being emptj^. 



The club-shaped paraphyses are composed of from 6 to 7 cells 

 much longer than broad below, about equal in length and 

 breadth above ; either a single paraphysis, or two together, or 

 a paraphysis and a sporangium arising from a single cell of the 

 vertical filaments which compose the thallus. 



Captain Carmichael's description and figure of his Linckia 

 clavata are very inadequate, and as none of his original specimens 

 are known to exist, there must always remain a certain amount 

 of doubt as to whether his plant was identical with the present 

 species. 



* In Mr Holmes's copy of Crouan's Algnes Marines dn Finistere, no. 56, 

 is, in my opinion, a stunted specimen of Ralfsia verrucosa, and Dr. Hauck 

 tells me this is also the case in his copy. Dr. Bornet, however, in a letter 

 to me concerning my Berwick plant, says : — " C'est bien ce que je connais 

 sous le nom de Myrionema clavatum, Carmichael (Ralfsia clavata, Crouan, 

 pro parte)." 



