348 



THE JOURNAL OF BOTANY 



1. A. sarniensis, sp. n. Frons pellucide articulata, fastigiata, 

 erecta, ecorticata, tenui-filamentosa, rejDetite secunde kteraliter ramosa 

 ramulis fasciculatis. 



About 1-1^ inch in height ; epiphytic on other algre ; an exceed- 

 ingly beautiful and delicate plant of a deep rose-red; first found 

 in fine fruiting condition Oct.-Dec. 1921, in great abundance in 

 almost every rock-pool at about half-tide ; later on it was less plen- 

 tiful, but doubtless persisted through the winter, as fully-grown 

 sterile specimens were gathered in May (Fig. 1). 



The main branches are widely divergent, giving off at first irre- 

 gular and then alternate secondary branches from below the articula- 

 tions. Each joint bears 2-3, rarely 4, ramelli, any one of which may 

 in turn develop into a branch of indefinite growth. Towards the 



Fig. 2. — Antithamnionella sarni- 

 ensis. X 45. 



Fig. 2 a. — Antithamnio- 

 nella sp.rniensis. Verti- 

 cils with 2-4 ramelli. 

 X 100. 



extremities the whorls become very dense and ocellate in appearance • 

 the branches are obovate in outline and tufted or plumose (Fii ^ "> a) 



The older portions of the stem are naked or clothecf with 2 

 rarely 3, ramelli, 10/. x 18;., and about 230^ in length, any of 

 which niay be replaced by a discoid rhizoid. The rhizoids are non- 

 septate, irregular m outhne, and almost colourless (Fig. 3). 



The cells of the main branches measure 190 x 60 u-70 // x 50 « 

 The cell-membranes are pellucid, extremely thick, and laminated ; i!; 

 the oldest parts of the plant they vary from a quarter to nearly equal 

 the diarneter of the central lumen-12 to 15;.. The joints are 

 pertorated, a distinct pore is visible on each side of the septum 



Cystocarps and antheridia have not yet been observed. The 

 sessile tetrasporanges are borne on the upper branches at the base^ of 



