142 
Campbell . — The Gametophyte and 
length and about half as wide. In size it is intermediate between B. Lunavia 
and B. virginianum . 
The youngest specimens available (PL VIII, Figs, i, 2) were broadly oval 
in outline, f to i\ mm. in length, and the antheridial ridge had not yet 
developed. These young specimens had numerous long rhizoids, which 
are much less conspicuous in the more advanced stages. 
As the gametophyte develops, it becomes relatively narrower, and often 
less regular in outline, and a more or less conspicuous median ridge is 
formed, upon which are borne the antheridia (Fig. 3). These begin to 
develop before the archegonia make their 
appearance. The latter usually occur close 
to the flanks of the antheridial ridge, but 
not upon it. 
A longitudinal section of the young 
gametophyte shows the apex to be occu- 
pied by a group of meristematic cells, but 
it is not certain that there is a definite 
single apical cell, although the cell, x, in 
Fig. 8 may be such a single initial cell. 
As in other Ophioglossaceae, there is 
present an endophytic fungus which occu- 
pies a large part of the inner tissue of 
the gametophyte, but is absent from the 
meristematic region. In the older game- 
tophyte it does not invade the tissue im- 
mediately adjacent to the reproductive 
organs (Fig. 12), and a section of the 
gametophyte shows the dorsal region nearly 
or quite free from the fungus, which is 
abundantly developed in the ventral region. 
In the infested area the fungus hyphae fill 
the cell cavity, but the nucleus remains 
intact, as has been noted in other cases (Fig. 10). 
The endophyte of B. obliqnum closely resembles that of B. virginianum , 
and, as in that species, there may be developed thick-walled spores (?) 1 
(Fig. 10, sp). 
Jeffrey 2 thinks that the endophyte is related to the genera Pythium 
and Completoma , but has not proposed a name for it. 
No further study of the endophyte was made, as it does not seem to 
differ materially from that of B. virginianum. 
Text-fig. 1 . a. Gametophytes of 
Botry chium obliqnum, Miihl., some with 
attached sporophytes. x about 3. B. 
Young sporophyte with expanded coty- 
edon, attached to the gametophyte. 
Pro. natural size. From photograph 
by Dr. H. L. Lyon. 
Campbell: loc. cit. 
2 Jeffrey : loc. cit. 
