On THE PITHOPHORACES. 57 
eask-shaped with the upper end conical and the top somewhat rounded. Twin 
spores occur not seldom, and are formed by terminal cells as well as by inclosed 
(pl.-6, figs. 4, -5. s', s”). ; 
The rhizoid part. Only two of the examined specimens have been so 
perfect as to have the rhizoid part of the thallus remaining. In the one, repre- 
sented pl. 6, fig. 2, the rhizoid consists of four vegetative cells forming a single 
series. In the other, represented pl. 6, fig. 3, the rhizoid has an uncommonly pow- 
erful development. It is richly ramified, with branches even of two degrees, and 
is also sporiferous, having both terminal and inclosed spores. In neither specimen 
the limit between the cauloid and the rhizoid is so strongly marked as is usually 
the case in Pithophoracee. 
Sterile specimens resemble the fertile essentially as to their ramification. 
The branches of the 1:st degree are, however, still more frequently placed opposite 
in pairs to each other (pl. 6, fig. 1). --. Only in one specimen I have seen the 
rhizoid part of the thallus, and in this it consisted of only one cell (pl. 6, fig. 1). 
Measurements. Fertile specimens. The cauloid. The vegetative cells 
of the principal filament are on an average 70 w thick. The smallest thickness 
observed is 55 w and the greatest 90 uw. The vegetative cells in the branches of 
the I:st degree are on an ay. 58 « thick. They vary between 50 w and 70 u. 
The thickness of the branches of the 2:d degree is on an av. 55 w, and of those 
of the 3:rd degree 53 w. The length of the vegetative cells varies between 5 and 45 
times the thickness. The top cells are the longest, as usual. — The inclosed spores are on 
an ay. 114 w thick and 230 w long. The limits of variation are indicated by on 
15 159 w. The terminal spores are on an av. 95 mw thick and 214 w long. They 
vary between ®- (0) 30) . 
The rhizoid. The thickness of the principal filament is on an av. 60 p, 
that of the branches of the l:st and 2:d degree 50 uw. The length of the rhizoid 
cells exceeds the thickness 6 to 40 times. The spores which Ihave found in the rhizoid 
of the specimen represented pl. 6, fig. 3 are, the inclosed one 100 w thick and 
255 w long, and the terminal one 85 w thick and 240 uw long. 
Sterile specimens. The cauloid. The thickness of the principal filament: 
is on an ay. 86 uw. It varies between 85 w and 90 uw. The branches of the 1:st 
degree are on an ay. 72 w thick, those of the 2:d 65 mw, and those of the 3:rd 60 «. 
The length of the cells varies between 6 and 50 times the thickness.. The rhi- 
zoid of the single specimen in which I have had occasion to observe this part 
of the thallus, was 55 w thick. 
Affinities and Differences. P. ocdogonia (Mont.) nob. is most nearly related 
to P. kewensis nob. It differs from this species, as well as from the other species 
belonging to this section (P. isosporee) by a considerably stronger development of 
the system of ramification in the sterile specimens as well as especially in the fer- 
tile ones. But one of the other species possesses branches of the 3:rd degree, and 
in no ‘one of the others opposite branches occur so often in the fertile specimens. 
Characteristic in this species are also the frequent occurreuce of subsporal branches 
and of twin spores. 
Nova Acta Reg. Soc. Sc. Ups. Ser. III. 8 
