KONGL. SV. VET. AKADEMIENS HANDLINGAR. BAND. 20. N:0 5. 185 



supposition of this algologist that the plant grows attached to stones. It is probably 

 litoral. 



Locality: Greenland. 



Rhodochorton Rothii (Turt.) Näg. 



Ceram. p. 35,5. Conferva Rotliii Turt. Syst. 6, p. 1806; sec. Dillw. Brit. Conf. t. 73. 



f. typica. 



Descr. Callitliamiiion Eof.hii J. G. ÄG. Epicr. p. 13. 



Fig. Thamiiiflium Eol.liii Thur. in Le Jol. Liste Alg. Cherb. t. 5. 



Exsicc. » n Aresoh. Alg. Scand. exsicc. N:o 259. 



f. globosa nob. 



Planta globosa, densissirae iiitertexta, diametro vix 2 mm., plexu basali e filis repentibiis ramosis, con- 

 lertis constante, systemata ramonim, cvebcrrima, fastigiata, deiise i-adiatim disposita emittente; axi primavio ra- 

 raonim systeraatiim paullo supva basim in fasciculo ramoi'um soluto, ramis raro siinplicibus, vulgo proesBrtim 

 supra niedinm ramulis plus minus crebris, elongatis, adpressis, approximatis, seeundis, vcl alternis obsessis; arti- 

 culis inferioribus ramorum diametro fere lequilongis, eirca 14 //. crassis, summis ramulorura diametro saltera 

 3-plo longioribus, vix 5 u. crassis; ramis tetrasporangiferis subapioalibus. Tab. 15, fig. 9 — 13. 

 Syn. Callithamnion floridulum Lyngb. Hydr. Dan. p 130, tab. 41 1). 

 » » SOMMERF. Suppl. p. 193. 



» Rothii Croall, Fl. Disc. p. 460. 



» » DicKiE, Alg. Sutherl. 1. p. 143; Alg. Cumberl. p. 239. 



» » SOMMERF. Suppl. p. 193. 



Thamnidium » Kjellm. Spetsb. Tliali. 1, p. 27; Algenv. Murm. Meer. p. 25. 

 B » Kleen, Nordl. Alg. p. 22. 



Description of f. f/lobosa. The plant forras almost globular, dense, solid tufts, 

 whicli are about 2 mm. in diameter and who.se eolour inclines to violet (fig. 9). Its 

 basal portion is composed of densely intertwisted, procumbent, branching filaments (fig. 

 10). From these there issue radially fastigiata, dense, very densely congested branch- 

 systems (fig. 11), having a short, raore or less curved, main axis about 14 ,w. thick at 

 the base and formed of slightly tun-shaped cells which are about as long as thick. 

 This axis is divided into a more or less dense bunch of branches which at their base 

 are of about the same thickness as the main axis or the secondary axes from which 

 they arise, but taper equally and strongly towards the tip, so that thcy are here scar- 

 cely half as thick as downwards. The cells are also elongated upwards, so that, from 

 being in the lower portions of these axes slightly tun-shaped and about as long as 

 thick, they become quite cylindrical and three times longer than thick (fig. 12, 13). 

 These branches are rarely simple, generally throwing ont nearer the base one or two 

 and above their iniddle tAvo or more, erect, appressed side-axes composed of cylindrical 

 cells, attaining the same height as their respective primär)' axis and tapering upwards 

 like this, thougli only slightly. The branches bearing tetrasporangia seem to be subapi- 

 cal as in the typieal form. The present form diflfers from this by its hal>it and richer 

 branching and by the cells being different as to size, length, and thickness in the upper 

 and lower part of the frond. 



K. Vet. Akad. Haniäl. Bd. 20. N:o 5. ''■4 



