of Lycopodium clavatum , L. 295 
have not been observed in the case of the Fungus inhabiting 
the prothallus of L . clavatum . 
Neither the structure of the mycelium nor the presence of 
the multinucleate vesicles, the nature of which is uncertain, 
afford sufficient indication of the group to which this endo- 
phytic Fungus belongs. The appearance is quite consistent 
with the position, as one of the Peronosporeae, which has 
been commonly assigned to the similar endophytes found in 
the prothalli of other species of Lycopodium ; but fuller 
knowledge of its reproductive organs and life-history is 
needed before the question of its systematic position can be 
settled. 
The Fungus comes into relation with the surrounding soil 
by means of hyphae which are present in many of the 
rhizoids. One or more hyphae,* the continuity of which with 
the mycelium in the underlying tissue can be traced, may 
be found running almost parallel within the cell-cavity of 
a rhizoid (P'ig. 35). In passing through the basal wall of the 
latter, the hypha is surrounded by a short sheath derived 
from the perforated cell-wall. The presence of similar sheaths 
has been described and discussed by Jeffreys 1 in the case of 
the Fungus inhabiting the prothallus of Botrychium virgini - 
anum ; but there the sheaths follow the hypha as it passes 
inwards through the outer cell- walls. In L . clavatum , on 
the other hand, the ^heaths project outwards into the cavity 
of the cell which bears a rhizoid (Fig. 36). This difference is 
not without meaning, for it affords indirect evidence that the 
hyphae penetrated from the interior of the prothallus into 
the rhizoid, and are therefore not to be regarded as infecting 
hyphae. Probably after passing along the rhizoid, the 
filaments of the Fungus penetrate its wall and ramify on the 
soil, as has been described for L. annotinum 2 . 
In concluding this account of the prothallus of L . clavattim , 
one or two biological points which can be inferred from the 
study of its structure may be referred to, though they can at 
1 Trans. Canadian Institute, 1896-7, p. 273. 
3 Bruchmann, loc. cit,, 1885, 
