New Marine Fungi on Pelvetia. 37 
Very early in the season smaller and differently shaped 
perithecia were observed. These appeared to be pycnidia, but 
unfortunately no pycnidiospores were found in the material collected. 
The mycelium of this fungus seems to occur in every thallus. 
Thousands of plants have been collected and sectioned from stations 
representative of the North and South, of the East and West coasts 
of Britain. All showed the fungus; in fact no plant, examined by 
the writer hitherto, has failed to show it in profusion. In addition, 
herbarium material at Kew has been gone over with the same result. 
These specimens were representative of Europe generally, and of 
collections made from the beginning of last century to the present 
day. This would seem to confirm the writer’s view that this union 
of alga and fungus is general. It is quite possible, however, that 
oospores may germinate and plants reach maturity without infection. 
It will be interesting to determine whether this is so, and also to 
find out the distribution of such plants if any occur. 
The wide, and it may be universal, occurrence of the mycelium 
along with Pelvetia at once raises the question of the relationship 
of the two. Experiments have been initiated with a view to determine, 
if possible, the part played by both in this symbiotic union. It may 
quite well be that the presence of the fungus has something to do 
with the plant’s ability to withstand exposure for so long after 
submersion. Observations in the laboratory have shown that the 
loss of water from the thallus is very slight. But here again it is 
too early to make definite assertions as the experiments and obser¬ 
vations are still incomplete. 
STIGMATEA PEL VETIJE NOV. SP. (Fig. 2, 1—6). 
Perithecia arranged in almost concentric rings on blackened 
patch, sunk in tissue, forming hemispherical protuberances with 
flat or occasionally rounded bases, remaining covered by blackened 
tissue except at point broken by irregular ostiole, large, 160-200/a 
in diameter. Peridium only distinctly formed near tip. Asci 
cylindrical, long with slightly thickened apex, 100-120/a x 12-14/a, 
8-spored. Paraphyses present, branched and unbranched, septate. 
Ascospores egg-shaped, 22-25/a x 9-12/a, hyaline, uniseptate, with 
distinct constriction. Pycnidia smaller, pyriform, with thick black 
walls, 70-85/a, at first sunk, but becoming superficial; pycnidio¬ 
spores 3 x 1'5/a. 
Hab. Parasitic on thallus of Pelvetia in Scotland. 
This fungus is parasitic, attacking the thallus and doing such 
damage as frequently to sever branches from the basal portions. 
