75 



little independent, and, perhaps, it might merely be regarded as a 

 monstrosity than a difference of type. In this as well as the typi- 

 cal form the edges of a hollow and in the lower part opened 

 specimen, partly involucrated partly not, often grow inwards and 

 by and by replenish the opening, forming a somewhat concave 

 base. However, now and then the plant may open itself in the 

 part turning upwards. So also in regard to old and cup-shaped 

 or whorl-shaped individuals. Even here the edges often grow in- 

 wards, or new but frequently short branches issue from the lowe r 

 and more or less rubbed part of the plant, by and by even deve- 

 loping more vigorous branch systems, though frequently composed 

 of short and thinner branches. 



I met with a form growing in very dense banks and closely 

 related to the typical form of this species, partly in the same partly 

 in another locality than the latter. It keeps a hemispherical shape 

 for a longer time and often not opening itself or getting hollow, 

 but the lower part even developed more downwards than usual 

 and on the other hand rather rubbed and denudated in the part 

 that has turned upwards, or here even concave, often with some- 

 what coarser, very dense and upwards much anastomosing bran- 

 ches, with obtuse ends. In the part that has turned towards the 

 bottom and otherwise it accords with f. typica, therefore, I do not 

 record it an independent, but merely a local form of the species, 

 caused thereby that the individuals have been closely heaped 

 together. 



A coarser form from Huso in Sogn may perhaps be referrible 

 to this species. I, however, have seen but two fragmentary, stunted 

 and in the part turned upwards somewhat denudated specimens, 

 collected in a ,,deep litoral lagoon" by P. Boye. As they also 

 are sterile, they cannot be determined with any degree of certainty. 



With reference to the structure the present plant most nearly 

 •accords with L. dimorphum or the species resembling it. ln a 

 longitudinal section of a branch the cup-shaped layers of tissue 

 ■are distinct and pretty regular, with the inner cells frequently rect- 

 angular, 10—15 /i long and 6 — 9 p- broad. 



The conceptacles of sporangia are partly somewhat scattered 



