368 
3. Antithamnion boreale (Gobi) Kjellman. 
Kjellman, Norra Ish. algfl. 1883 p. 226, PI. 16 figs. 2—3 (Alg. Artc. Sea p. 180); Reinke, Algenfl. westl. 
Ostsee 1889, p. 23 (f. baltica), Atlas deutsch. Meeresalg. I 1889 Taf. 22; Kylin 1907, p. 173. 
Antithamnion Plumula var. boreale Gobi, Algenfl. des weissen Meeres. St. Petersbourg 1878, p. 47. 
While in a former paper (Gronlands Havalger, 1893, p. 787; Ann. sc. nat. 7° ser. 
t. 19, 1894, p. 64) I have regarded this species as a variety of A. Plumula, in ac- 
cordance with Gost, my later investigations of the Danish 
specimens have led me to agree with KJELLMAN’s view 
that it must be considered as a distinct species. Ac- N \ \ | 
cording to KJELLMAN | \ À 
and other authors it (| N) 
differs from A. Plu- \\ N i 
mula by being more \ : NS A 
slender, by ionger cells N NS Lee 4 
in the long shoots, by i W i 
the pinnæ in great \ X 
part bearing pinnulæ \ /] 
on two sides and then N 
opposed or alternate, N V4 t 
while the pinnæ of / 
A. Plumula bear only [ Ye 
pinnul on the upper \ 
side, and by the spor- À / 
angia being always i 
sessile. KyLIN adds the 
Fig. 304. character that A. bore- 
Antithamnion boreale. Lower part of plant. 2 2 B Ya | 
msi. ale is sporangia-bear- 
ing early in June while 
in A. Plumula the sporangia appear only in July. I can 
confirm these statements and add a little more. eo 
The base of the plant resembles that of A. Plumula, i 
as shown in fig. 304 where free descending filaments are i 
given off from the cells of the main axis and the ( N 
proximal part of the pinnæ. Fig. 305 shows the lower l) 
part of a plant gathered in April. The lowermost part Rp 
which is short-celled and had a darker colour had un- AN 
doubtedly been formed in the foregoing year while the \\ 
upper, brighter and more long-celled part of the shoot À 
had grown out in spring. The first pinnæ are unbranched Fig. 305. 
and the next following ones bear only one or two pin- uAntithamnion boreale. Specimens 
nulæ on the upper side. gathered in April. The lowermost 
z part (shaded) is a survival from the 
The shoots usually bear two rows of pinnæ; how- foregoing year. 95:1. 
