. Carnegie Institution of Washington publication. THE GAMETOPHYTE 21 starch) which is left in the cells. It is not clear what role the endophyte plays in the manufacture of the reserve food materials upon which the further growth of the prothallium depends. It is highly probable, however, that some of the necessary organic elements are derived from the destruction of the fungus tissues which serve as food for the further development of the prothallium. While no data are at hand to prove this, the lack of permanent growing tissue in the prothallium and the com- plete destruction of the fungus m
. Carnegie Institution of Washington publication. THE GAMETOPHYTE 21 starch) which is left in the cells. It is not clear what role the endophyte plays in the manufacture of the reserve food materials upon which the further growth of the prothallium depends. It is highly probable, however, that some of the necessary organic elements are derived from the destruction of the fungus tissues which serve as food for the further development of the prothallium. While no data are at hand to prove this, the lack of permanent growing tissue in the prothallium and the com- plete destruction of the fungus make it highly probable that the life of the gameto- phyte in Helminthostachys is restricted to a single season, as it is in Ophioglossum Fig. n. A. Male gametophyte of Helminthostachys. X8. C. Surface view of ripe antheridium, showing opercular cells B. Young antheridium. X::;. D. An old archegonium. X about 200. (Figs. A-C, after Lang.) THE ENDOPHYTE. 1 he endophytic fungus which inhabits the gametophyte in all of the Ophio- glossacea? is very much alike in all of the species, differing only slightly in size m different forms (fig. 9). A special study was made of this endophyte in Ophio- glossum pendulum, where it is especially well developed. As we have already seen, the endophyte is absent from the younger parts of the prothallium, but in the older parts it is exceedingly conspicuous. Sometimes fragments of a fungus are found outside the prothallium, growing in the humus, and these are evidently the same forms that infect the very young prothallium when it arises from the germinating spores. These external hyphae in some cases have an occasional septum, and this is also the case in those forms which infect the young prothallium. In all of the hyphae seen within the prothallium, however, these septa seem quite absent. I he infection of the prothallium through the rhizoids has been noted in all the species, but, as we have already stated, it is probable that the e
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