204. MR. A. D. COTTON ON 
those of the ordinary large cells of the thallus. This is parti- 
cularly obvious in the ease of antheridia, which form broad 
patches on the surface of the ordinary frond. When Endoderma- 
filaments pass over such patehes their appearance is entirely 
altered. The regularity in width is lost, and very fine filaments 
are often formed with swollen portions occurring at intervals. 
Such alteration in the form of cells, which is often noticeable 
even in the case of individual filaments, is instructive as showing 
that the character of the tissue of the host-plant may materially 
affect the form of the cells of the invader. It is not likely that 
food-supply is in question here, as Endoderma is not regarded 
as being parasitic. It may be that the growth of the antheridial 
cells may be more rapid thau that of the endophytic filaments, 
and thus the latter may assume an irregular course. The fact 
above referred to is not without importanee when defining 
specific differences. In dealing with endophytes, allowance has 
to be made for the host-plant and too much weight must not be 
attached to minute morphological differences. 
The remarks which follow relate to the presence of Endoderma 
viride forma Nitophylli on other hosts. A large number of in- 
fected species of Ceramium, Chylocladia, and other red alge have 
been examined ; but it is difficult in. most cases to speak with 
certaintly as to the identity of the endophyte they contain. 
The fruiting material is rarely obtainable. In some cases two or 
even more species are probably present, though undoubtedly 
some species are very variable in appearance. A further account 
will, it is hoped, be published later, when the life-history of 
other species is better known and it will be possible to speak 
with more certainty as to their identity. 
The following observations have so far been made :— 
Nitophyllum punctatum.— E. viride is not infrequently found 
in this species ; the attacked areas are, however, not so diffused 
as in N. Hillie, but more often have the form of bright green 
spots. Zoosporangia are freely produced, they are considerably 
smaller than those described above, but this is not considered as 
a point of sufficient importance to cause the plant to be regarded 
as a distinet species. 
N. Bonnemaisoni.—Often present, covering large areas; 
fruiting specimens scen. 
N. Gmelini.—Commonly present ; fruits rarely found. 
N. versicolor.—This rare British species when found often 
