385 
56. PL plumosa (L.) Ag. Kjellm., N. I., p. 218 (173); Lyngb., 
Hydrophyte p. 38. 
This is generally a sublittoral 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 may also be 
found in fjords in sheltered localities. It occurs most frequently 
as an epiphyte especially on the stems of Laminaria hyperborea, 
of which plant it is a characteristic epiphyte, and on which it grows 
luxuriantly. 
Tetraspore-bearing plants were found from May to November, 
cystocarpic in May, June, August, October and December. 
This is a very common species of the Faeroese coasts, as already 
noted by Lyngbye (l.c.), who writes: — »Ad insulas Faeroenses in stipite 
Laminariae digitatae copiose«. 
It was first reported by La n dt, l.c. p. 231. 
ANTITHAMNION Nagl. 
57. A. floccosum (Mull.) Kleen, Nordl. Alg., p. 21; Kjellm., N. 1., 
p.225 (179); Conferva floccosa Muller, whose figure in Flora Danica, 
tab. 828, fig. 1, is, however, not very good; the specimens from the 
Faeroes come near to Harvey’s figure in Phycol. Brit., tab. 81; Calli- 
thamnion Plumula ft pusilla Lyngb., Hydrophyt., p. 127, tab. 39. 
The Faeroese form must be referred to var. atlantica J. Ag. (Spec. 
Alg. vol. Ill, 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 may add that this species appears to me 
a decidedly good one, quite distinct from A. Plumula (cfr. Rosen- 
vinge, Gronl. Havalg., p. 789). 
Along the coasts of the Faeroes it is most commonly met with 
in the littoral zone or in the upper part of the sublittoral, 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 6 cm. long, while those from exposed 
localities — from between tide-marks where they grew epiphytic 
on Lithothamnion — were only 1—2 cm. long, about the size of 
Callithamnion scopulorum. Lyngb ye found it in the sublittoral 
zone, the Callithamnion scopulorum 0 pusilla recorded by him in 
Hydrophyt., p. 127, being this species, as has been proved by exa- 
