394 
mentioned here and which are pointed out by Kj ell man as the 
chief marks of distinction between his Rh. intermedium and Rh. Rothii 
cannot be regarded as denoting a distinct species, for I have found 
all intermediate stages between the former species and typical Rh. 
Rothii, which Jonsson 1 also claims to have done in the Icelandic 
material. Perhaps it may be regarded as a special form of Rh. Rothii, 
but at any rate the name intermedium is hardly correct, it being by 
no means intermediate between the former species and Rh. flori- 
dulum — as Kj ell man supposes — the latter being quite distinct 
from Rh. Rothii , e. g. by its star-like chromatopliores. 
Rh. Rothii occurs not only in the littoral zone but also in the 
sublittoral on Laminaria hyperborea — as I quite agree with Jons¬ 
son (1. c. p. 147) in thinking that the Rhodochorton , which is com¬ 
monly met with on the stems of Laminaria hyperborea where it 
occurs as a short, dense mat, is this species, and I am also of 
opinion that Rh. parasiticum Batters 2 undoubtedly belongs to this 
species as pointed out by Jonsson. Fig. 63 shows the basal 
part, the erect filaments spring from prostrate ones creeping on La¬ 
minaria hyperborea. How far this alga is really a parasite or only 
a pseudo-endophyte as mentioned by Jonsson I shall not discuss 
at any length, merely stating that where it occurs on the Laminaria 
the tissue of the latter is always more or less destroyed, and there¬ 
fore Jonsson is very possibly right when he says that it can 
only penetrate into the tissue, after the latter has been destroyed. 
A single specimen which I found on a Laminaria -stipe which 
Jonsson had gathered from Kalbakfjord differed in some points. 
Fig. 64 shows some small portions of it. Besides the clustered tetra- 
sporangia commonly occurring on Rhodochorton Rothii (see fig. 64 b) 
it had also, as shown in fig. 64 a, solitary, terminal sporangia, 
which were noteworthy by being much larger than the former, the 
tetraspores in the clusters being 16 p broad, while the solitary ones 
attained to a thickness of some 27 p. The solitary sporangia were 
borne on short, erect filaments, which were generally branchless; 
the cells in these filaments were for the most part short, often only 
just as long as broad, and frequently somewhat swollen in the 
middle. On the other hand, the filaments bearing the clustered 
1 Jonsson, H.: The marine Algse of Iceland (I. Rhodophycese). Botanisk 
Tidsskrift. 24. Bind, p. 146. 
2 Batters: New or critical British marine Algte (Journal of Botany, vol. 34, 
1896, p. 389). 
