EOW-WATEE MAEK. 81 



scope to discern the difference ; some are so minute as 

 to appear but as a fairy fringe on the edge of sea-grass 

 Zostera, or a velvety substance on mud-covered rocks, 

 or a pencil of rose-coloured filaments on Ceramhtm 

 Itubrum, or a mere blotch on the old sea-beaten stems 

 of Laminaria Digitata. 



On paper they form the prettiest little trees laden 

 •with fruit, and under the microscope the structure 

 and colour are perfectly beautiful. They are not dim- 

 cult to recognize if vre attend to the following direc- 

 tions : — The tufts are usually fine, small, silky and 

 soft to the touch: floating out in the water, the 

 slender, rosy, and often much-branched filaments with 

 dots along the branches will arrest attention; and 

 these are the 



Generie character. — Frond rosy or brownish-red, 

 thread-like, with an opaque and cellular or translucent 

 and jointed stern. Each joint has a single long cell 

 of colour, and the intermediate space is white and 

 transparent. 



The fruit, quite different from that of Polysiplionia, 

 consists of a number of berries inclosed in an envelope, 

 called favellcB, and tetraspores are scattered along the 

 branchlets, giving the dotted appearance I referred to 

 above. 



There are twenty-five species of this plant, and 

 most of them are common on the shores of Great 

 Britain and the Channel Islands. 



Callithamnio^- Teteagokttm (Square-branched 

 Callithamnion). — This is one most likely to mislead 

 a beginner because of its robust habit and size, also 



