F. Børgesen: List of species. 



423 



Fig. 404. Chætomorpha brachy- 

 gona Harv. Two forms. Com- 

 pare text. (About 200:1). 



after division only half their length. 



The zoosporangia, have nearly the 



same shape, though often a little 



swelled in the middle. In this form 



the upper end of the basal cell is 



about 40 // broad ; the vegetative part 



of the filaments is 65 // broad, and 



the sporangia 70 a broad. 



Parts of a very similar form is 



figured in Fig. 403 rf, e. The vegetative 



cells in this plant reached a breadth 



of about 50 //. 



Finally in Fig. 404 a, b and c, d 



two more narrow forms are figured. 



Their vegetative cells vary in thick- 

 ness from 35 — 45 /y. With the excep- 

 tion of those quite close to the base the cells in these forms are 



very short, often reaching not half their breadth. 



The specimens here described and figured are only to be 



considered as samples. Between them specimens may be found 



connecting them all gradually 

 as to shape and size of the 

 cells. 



These forms were all 

 growing together in an ex- 

 posed locality and found in 

 company with Enteromorpha 

 plumosa, Pylaiella jiilvescens 

 and the below mentioned 

 Rhizocloniums. 



St. Jan: Christiansfort on 

 steep rocks facing the open sea 

 at about high water mark or a 

 little above. 



22. Chætomorpha gracilis 



Kütz. 



Besidesthe detached form 



Fig. 405. Chætomorpha gracilis Kütz. mentioned in vol. I, n. 19 I 



a, b, c, parts of a filament, d, base of r j ^ r j 



another plant. (About 150:1.) have moreover found a fixed 



