— 151 



and 7 — 10 fi broad, they are for the most part sessile, especially in the 

 marginal portion, but stalked sporangia are not rare in the central part. 

 The stalk is of varying length and composed of one or more cells. The 

 sporangia are usually thickest in the middle or sometimes ' at the base, 

 and consist usually of two series of loculi in the middle and one series 

 below and above. The chromatophores are small, disciform, 4 — S in each 

 cell. Unilocular sporangia are unknown. 



I have also met with some fragments of an Ascocyclus on Laminaria 

 saccharina, fully agreeing with the specimens on Rhodymenia. 



The species differs from Ascocyclus orbicularis Magn. and A. affinis 

 Svedel. by shorter ascocysts and the presence of assimilative filaments. 

 From A. hispanicus Sauv. it differs by the number of the chromatophores, 

 unbranched erect filaments and the shape of the ascocysts, amongst other 

 characters. From A. sphærophorus Sauv., to which it comes nearest, it differs 

 by the shape of the ascocysts, which in A. islandicus always are sessile in 

 A. sphærophorus sometimes stalked. The sporangia of A. islandicus are 

 somewhat narrower and the assimilative filaments somewhat longer than 

 in A. sphærophorus. The differences mentioned between A. islandicus 

 and A. sphærophorus were probably not of sufficient value to keep them 

 specifically distinct, if the number and shape of the chromatophores were 

 the same. The chromatophores of A. sphærophorus are, as far as t know, 

 unknown, and I prefer therefore to regard the Icelandic plant as a distinct 

 species, at all events provisionally. 



Gathered with plurilocular sporangia in Sept. 



NW. I c el. Kolbeinsâ. 



Fam. Ectocarpaceæ. 

 Microsyphar Polysiphoniæ Kuck. Beiträge p. 29. 



I have found this species growing in Polysiphonia urceolata and 

 Gallithamnion scopulorum. Gathered with sporangia in June and August. 

 NW. Icel. Isafjöröur (G. O.). 



SW. Icel. Brinmes, Einarslön; Reykjavik, Njarövik (G. O.). 



Streblonema æcidioides Rosenv. Grl.Havalg. p. 894, Deux. Mém. p. 80. 

 Phycocelis æcidioides Kuck. Bemerk. I, p. 234. 



I have found this species growing in Laminaria saccharina and Lami- 

 naria digitata f. cucullata in the upper sublitoral region. I have also 

 met with it in litoral pools in Laminaria saccharina f. phyllitis. Gathered 

 with plurilocular sporangia in July — September. The Icelandic plants 

 agree well with the description and figures given by Pvosenvinge (1. c.) 

 and Kuckuck (J. c). Rosen vinge's original preparations of the species agree 



