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VIIL The endophyte. 
In the roots and prothallia investigated, the endophyte is 
abundant in all the species. It is, however, entirely lacking in 
the leaves, except B. silaeifolum. The fungus is also absent 
from the tissues inside the endodermis. Campbell (9) remarks 
that there is no essential difference between the endophyte in 
the Marattiaceae and Ophioglossaceae. The habit of the fungus 
agrees closely with that described by West (43), in the Marat- 
tiaceae (and even by that described by Cribbs for T'odea) except 
for the differences due to the symbiosis, the fungus being a 
parasite in WMarattiaceae, and a symbiont in Ophioglossaceae. 
The mycelium stains deeply with safranin and, in the older 
stages, also with Bismarck brown. It is multinucleate, even 
in the younger stages. 
The fungus penetrates probably by the endodermis and pro- 
ceeds through the outer parenchyma partly inter-, partly intra- 
cellular. The mycelium does not seem to stimullate cell division. 
On the contrary, in the regions where the cambial activity is 
strong, the fungus is invariably absent (West (43) holds the 
opposite opinion). At a definite distance from the epidermis 
the fungus branches copiously inside the cells (‘“arbuscles”’ 
of Gallaud) and disintegrates. The nucleus of the host-cell was 
not affected. The contents of these cells stain deeply with sa- 
franin. At other places the hyphae swell considerably, or they 
show a tendency to curl up till they fill the whole cell. Some- 
times these swollen forms suggest closely the suspensor of the 
zygospores in the Mucorineae. In other cells the so-called 
vesicles occur, thin walled, apparently osmotic products, 
filling sometimes the whole cell. Sometimes there occur two 
vesicles in one cell. In all these characters the fungus resembles 
closely the Sfygeosporium marattiacearumas described by West, 
except for the total absence of the resting spores as found by 
this author. This absence may be due to the different physiolo- 
gical conditions of the fungus (insufficient aereation). 
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