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 (Turtr.) NAa. 
Ceram. p. 355. Conferva Rothii Turr. Syst. 6, p. 1806; sec. Ditiw. Brit. Conf. t. 73 
f. typica. 
Deser. Callithamnion Rothii J. G. Ac. Epier. p. 15. 
Fig. Thamnidium Rothii Tour. in Le Jol. Liste Alg. Cherb. t. 5. 
Exsice. ¥ »  Arescu. Alg. Seand. exsice. N:o 259. 
f. globosa nob. 
Planta globosa, densissime intertexta, diametro vix 2 mm., plexu basali e filis repentibus ramosis, con- 
fertis constante, systemata ramorum, creberrima, fastigiata, dense radiatim disposita emittente; axi primario ra- 
morum systematum paullo supra basim in fasciculo ramorum soluto, ramis raro simplicibus, vulgo preesertim 
supra medium ramulis plus minus crebris, elongatis, adpressis, approximatis, secundis, vel alteruis obsessis; arti- 
eulis inferioribus ramorum diametro fere vequilongis, cirea 14 «. ecrassis, summis ramulorum diametro saltem 
3-plo longioribus, vix 5 «. crassis; ramis tetrasporangiferis subapicalibus. Tab. 15, fig. 9—13. 
Syn. Callithamnion floridulum Lynes. Hydr. Dan. p. 130, tab. 41 D. 
» » Sommerr. Suppl. p. 193. 
» Rothii Croan, Fl. Dise. p. 460. 
» » Dickie, Alg, Sutherl. 1. p. 143; Alg. Cumberl. p. 259. 
» » Sommerer. Suppl. p. 193. 
Thamnidium =» Kyetim. Spetsb. Thall. 1, p. 27; Algenv. Murm. Meer. p. 25. 
» »  Kueen, Nordl. Alg. p. 22. 
Description of f. globosa. The plant forms almost globular, dense, solid tufts, 
which are about 2 mm. in diameter and whose colour inclines to violet (fig. 9). Its 
basal portion is composed of densely intertwisted, procumbent, branching filaments (fig, 
10). From these there issue radially fastigiate, dense, very densely congested branch- 
systems (fig. 11), having a short, more or less curved, main axis about 14 «. 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 they are here scar- 
cely half as thick as downwards. The cells are also clongated 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, 195). 
These branches are rarely simple, generally throwing out nearer the base one or two 
and above their middle two or more, erect, appressed side-axes composed of cylindrical 
cells, attaining the same height as their respective primary axis and tapering upwards 
like this, though only slightly. The branches bearing tetrasporangia seem to be subapi- 
cal as in the typical form. The present form differs from this by its habit and richer 
branching and by the cells being different as to size, length, and thickness in the upper 
and lower part of the frond. 
9. 
K. Vet. Akad. Handl. Bd. 20. N:o 5. ad | 
