385 



56. Pt. plumosa (L.) Ag. Kjellm., N. I., p. 218 (173); Lyngb., 

 Hydrophyt., p. 38. 



This is generally a sublitloral species and has been found down 

 to a depth of some 20 — 25 fathoms, but it is also met with near 

 low-water mark in caves and rock-pools growing attached to rocks 

 and stones. It seems to prefer exposed coasts, but mav also be 

 found in fjords in sheltered localities. Il occurs most frequently 

 as an epiphyte especially on the stems ol Laminaria hyperborea, 

 of Nvhich plant il is a characteristic epiphyte, and on which it grows 

 luxuriantly. 



Tetraspore-bearing piants were found from May to November, 

 cystocarpic in May, June, August, October and December. 



This is a very common species of the Færoese coasts, as already 

 aoted by Lyngbye Le), who writes: — »Ad insulas Færoenses in stipite 

 Laminariæ digitatæ copiose . 



It was lirst reported by Landt, Le. p. 231. 



ANTITHAMNION Nagl. 



57. A. floccosum (Miill.) Kleen, Nordl. Alg., p. 21 ; Kjellm., N. I., 

 p. 225 (179): Conferva floccosa Muller, whose figure in Flora Danica, 

 tab. 828, lig. 1, is, however, not very good; the specimens from the 

 Færoes come near to Harveys ligure in Phycol. Brit., tab. 81 ; Calli- 

 tham'nion Plumula pusilla Lyngb., Hydrophyt., p. 127, tab. 39. 



The Færoese form must be referred to var. atlantica J. Ag. (Spec. 

 Alg. vol. III, p. 22) because the lesser branches on the lower part 

 of the main branch are generally shorter than the articulation 

 whence they proceed, and I only exceptionally found them as long 

 or somewhat longer. I mav add that this species appears to rae 

 a decidedly good one, quite distinct from A. Plumula (cfr. Rosen- 

 vinge, Gronl. Havalg., p. 789). 



Along the coasts of the Færoes it is most commonly mel with 

 in the littoral zone or in the upper part of the sublitloral, and it 

 grows both on exposed and sheltered coasts, but on the latter it 

 appears to be of more luxuriant growth, the specimens I found on 

 sheltered coasts being up to t) cm. long, while those from exposed 

 localities — from between tide-marks where they grew epiphytic 

 on Lithothamnion — were only 1—2 cm. long, aboul the size of 

 Callithamnion scopulorum. Lyngbye found it in the sublitloral 

 zone, the Callithamnion scopulorum (i pusilla recorded by him in 

 Hydrophyt., p. 127, being this species, as has been proved by exa- 



