512 



the apex; the top cell is short. The cells are about as long as 

 broad, sometimes somewhat shorter, sometimes somewhat longer. 

 In the fully developed plant the main branches grow thinner to- 

 wards the apex (fig. 104 a and b). Lateral branches, and often even 

 the main ones, terminate in thin prolongations resembling rhizoids 

 (fig. 105 a); rhizoids growing downwards, occur frequently and most 

 abnndantly in the basal portion of the plant (fig. 104). The tips of 

 the rhizoids are often palmately cleft and serve as holdfasts (fig. 

 105 c). The hole through which the zoospores escape is fairly large 

 (fig. 104 b). 



This plant grew between tide-marks on a rocky, exposed coast, 

 where it occurred on the rock as a matted, dark-green growth, 

 3 — 4 — 5 cm j n height. 



Fruiting specimens were found in June. 



The present plant appears to agree fairly well with Acrosiphonia 

 flagellata Kjellm., but it also comes near to Acrosiphonia cincinnata 

 (Foslie) Kjellm. in many respects. 



It was gathered on Store Dimon(!). 



An Acrosiphonia which, in association with Enlcromorpha- species, 

 Chætomorpha tortuosa, eta, formed large, felted growths near Klaksvig 

 was somewhat similar to this plant. 



189. A. flaccida Kjellm. 



A single gathering appeared to agree fairly well with Kjell- 

 man 's description of the plant he calls A. flaccida. Both spiny 

 and hooked branches were absent. The chromatophore was finely 

 reticulate, with numerous pyrenoids. The cells were up to 200 /< 

 thick, i. e. somewhat thinner than recorded by Kjellman. My 

 specimens were unfortunately yet sterile. This species appears to 

 come very near to Acrosiphonia hijstrix (Stromf.). 



The gathering was collected in shallow water near Thorshavn in 

 the beginning of June (!). 



Acrosiphonia centralis Kjellm. is recorded from the Færoes 

 by Simmons, but a dried specimen of his plant gathered at Næs 

 (Oslero) which I examined appeared to he idcntical with .1. albescens. 

 And the same appears lo me to be the case with a plant gathered 

 by Rostrup and cailed by him Conferva arcta i. centralis Lyngb. 

 Nor have I found any specimens in my own inaterial which I 

 have felt justifled in referring lo .4. centralis as it is described by 

 Kjell man, and I cannol help entertaining some doubt as lo the 



