— 162 — 



an intermediate position between them. I doubt therefore that the division 

 of the genus Punctaria Grev. in the manner made by J. Agardh (1. c.) is 

 justifiable. 



E. I c el. Hölmanes (Strömfeit). 

 NW. I c el. Skâlholtsvi'k, Bi'ldudalur. 



Litosiphon filiforme (Rke.). 



Pogotrichum filiforme Rke. Atlas p. 62, Tab. 41, fig. 13—25; Rosenv. 

 Grl. Havalg. p. 869; Kuckuck Ueber Polymorphie bei einigen Phaeosporeen, 

 Festschrift für Schwendener p. 360. 



It grows in the upper sublitoral region in a depth of 1 — 5 fathoms, 

 especially on Laminaria saccharina. but it is also met with on Laminaria 

 hyperborea, L. digitata, Saccorhiza dermatodea and the stipes of Alaria 

 esculenta. It grows usually very gregariously, at all events on Laminaria 

 saccharina in the spring months in S.- and SW. Iceland, and covers the 

 host-plant, particularly the lamina, with a dense, matted growth, but it also 

 occurs solitarily. The Icelandic specimens attain a length of 1—3 cm., 

 and the fructiferous filaments are up to 116^ thick. In the spring months, 

 from the latter half of March to the first half of June, it was very abun- 

 dant in S.- and SW. Iceland, and it seems to attain its highest development 

 in these months. Specimens which I gathered in E. Iceland in the first 

 half of August, and in NW. Iceland in the beginning of September, were 

 composed of monosiphonous filaments with few, scattered plurilocular 

 sporangia; they grew solitarily and were poorly developed. 



In some stage of development this species reminds one of Ectocarpus, 

 Phæostroma or Leptonema as pointed out by Kuckuck (1. c), and such 

 plants I have not rarely met with in March — April. Rhizoids as described 

 by Rosenvinge (1. c.) and Kuckuck, are not rare in my material, and 

 sometimes I have seen them much more developed at the base of the 

 filament than figured by Kuckuck (1. c. f. 1 .). 



With plurilocular sporangia in March — August. 



E. I cel. Berufjöröur. 



N. Icel. Eyjafjöröur. 



NW. Icel. Prestsbakki, Kolbeinsâ. 



SW. Icel. Einarslön, Reykjavik (probably common). 



S. Icel. Vestmannaeyjar (probably common). 



Isthmoplea sphærophora (Harv.) Kjellm. Arct. Alg. p. 276: Rke. 

 Atlas Tab. 30 ; Pylaiella curta Fosl. Nye havsalger in Tromsö Museums 

 Aarshefter X, 1887, p. 181 ; Kjellm. Handbok p. 85; Fosliea curta Rke. 

 Atlas p. 45. 



This species occurs in the litoral region on other algæ e. g. Rhody- 

 menia palmata, Fucus inflatus, Gigartina a. o., and in the sublitoral region 



