112 KJELLMAN, THE ALGA OF THE ARCTIC SBA. 
pogon has not, from some cause or other, come to a normal development. It is also 
possible, that in certain cases the branch-systems destined to the formation of tetra- 
sporangia may, after some few reproductive cells are produced, develop themselves for 
vegetative purposes. 
The structure of the frond. Fig. 7 is a part of a cross-section, fig. 8 of a longi- 
tudinal section, of the main axis of the frond, near the base, of an older specimen. 
These sections show that the largest part of the frond consists of a parenchymatous 
tissue, whose thin-walled cells, that are destitute of or very poor in endocrom, dimi- 
nish gradually in size from within outwards, where they are surrounded by a cortical 
layer of small cells rich in endocrom, which layer is sharply defined from the inner 
mass of the tissue. The pericentral siphons as well as the central siphon are of in- 
considerable: width. 
The organs of propagation. The sporocarpia are ovato-urceolate, with a short 
neck. The spores are pyriform, about 100 w. long and 50 uw. thick. The tetrasporangia 
are large. The antheridia are slenderly cylindro-conical, greatly variable in size, but 
in general about 100 w. in diameter near the base. 
The other species of Rhodomela from Bohuslin, the Rh. subfusca f. extrateniensis 
vel normalis of J. EK, Argscnoue is clearly identical with Fucus subfuscus Woopw., Turn., 
Stackh. and Fl. Dan., and accordingly ought to be called Rhodomela subfusca (Woopw.) 
Ac. It is certainly a well-known species,. But in order to point out its discrepancies 
from the preceding one, I give figures on plate 8 referring to it, together with a de- 
scription of specimens from Bahnalons 
A first year’s plant, sterile, from a specimen from Bohuslan, taken in the month 
of December; fig 1. 
The plant becomes altogether black in drying and adheres firmly to the paper. 
The axes retain their terete form, or are at least only almost imperceptibly compressed. 
The hold-fast is a callus, from which issue oftentimes several systems of axes, in ge- 
neral unequally developed. My description refers to an one-stemmed, thinly branched 
specimen. A main axis is traceable only for some distance upwards in the frond. As 
elements of ramification we may consider, I think, 1) short cylindrically subulate 
branches, about 5—6 mm. in length; 2) fastigiate branch-systems of the same length 
with the preceding, whose primary axis bears a few side-axes only near the top; 
3) branch-systems, 5—8 cm. long, generally slenderly lanceolate, whose main axis bears 
side-axes of the two preceding types. These elements are combined in a more or less 
distinctly racemose manner. The racemose arrangement often becomes, however, diffi- 
cult to follow, because the main stem, as well as the primary axes in the branch-system 
of the first order, becomes sooner or later untraceable, a branch-system of the next 
higher order being developed of equal strength with the general axis above the point 
where the branch-system springs out. The difference in thickness between axes of next 
different orders in not considerable. The varieties I have observed with regard to the 
above-mentioned ramifications, are limited to the elements 1 being sometimes more 
numerous, sometimes less numerous than elements 2, and to elements 3 being now and 
then shorter than I have stated above. 
