69 



growing in shallow water, the part of the plant turning upwards 

 whitish or brownish-yellow, and the part turning towards the 

 bottom in general slightly darker, with a rather feeble rosy tinge, 

 seldom any stronger colour, but occasionally here and there getting 

 a lit tie darker in drying, if dried in the shade, or under cover. It 

 apparently ahvays develops itself freely on the bottom. Among 

 numerous specimens that I have seen, I have not met with any 

 fastened to or encompassing a stone or any other harder object. 

 Most of the specimens examined have been attacked by boring- 

 muscles especially in the centre of the frond and partly hollowed. 

 However, the solid central mass appears ahvays to be insignificant, 

 but an anastomose of the branches often takes place in a rather 

 early stage of development. The frond is repeatedly subdichoto- 

 mously branched, with axes of at least three orders, and the lower 

 axes frequently rather long. The branch-systems issue in all direc- 

 tions from the centre of the frond. In typically developed speci- 

 mens the branches are erect, fastigiate and straight, terete or a little 

 compressed, either cylindrical or slightly eniarged towards the tip, 

 more seldom feebly tapering in the part turned towards the bottom, 

 2 — 2.5 mm. in diameter, here and there furnished with short branch- 

 like or wart-like processes. In others, and especially if much 

 attacked by animals, the branches are rather irregular, somewhat 

 bent and more anastomosing. They are in the part of the plant 

 turned downwards occasionally a little spreading, and not so regu- 

 larly level-topped as in the part turned upwards, or in typically 

 developed specimens. The ends are, as a rule, in the first named 

 part obtuse, or here and there truncate, seldom thoroughly truncate 

 (pl. 10, fig. 2 — 4), but sometimes rounded especially in somewhat 

 spreading branched specimens. In the part turning upwards they 

 are nearly always at least partly truncate, or even disc-shaped. 

 Pl. 10, fig. 1, 5. In this part the tip of the branches may occa- 

 sionally be rather denudated, sometimes even in the lower part of 

 the plant, but now and then developing wart-like processes from 

 a truncate or denudated apex. Pl. 10, fig. 5 — 6. 



As remarked above, the plant nearly always is attacked by 

 animals, especially boring-muscles destroying the central portions, 



