THE GAMETOPHYTE 19 



observed the penetration of fungus hyphae into the rhizoids, and they believe that 

 the fungus which occurs within the thallus is, mainly at least, due to this method of 

 infection. From a comparison with the early infection of the young prothallium 

 in Ophioglossum, it seems to me more probable that the young prothallium in 

 Botrychium also is infected at a very early period and that the endophyte, once 

 established within its tissues, grows with the development of the gametophyte, the 

 secondary infection through the rhizoids of the older gametophyte being of minor 

 importance. 



In both species of Botrychium the infected region comprises the greater part 

 of the central tissue, leaving only a comparatively narrow peripheral region free 

 from the endophyte. This uninfected area is thicker upon the upper surface and 

 comprises the whole of the meristematic region, together with the developing sexual 

 organs. As in Ophioglossum, this uninfected tissue contains small starch granules 

 in considerable numbers, but not much else in the way of granular contents. The 

 invasion of the fungus results in the destruction of the starch and the accumulation 

 of large amounts of oil. This oil, according to Jeffrey, is not readily soluble in 

 alcohol, and the cells containing it, both in fresh and stained sections, appear dark- 

 colored. 



THE GAMETOPHYTE OF HELMINTHOST.H IIYS. 



The monotypic Hclminthostachys zeylanica is not uncommon throughout the 

 lowlands of the Indo-Malayan region and often occurs in large numbers. The only 

 account yet published of the gametophyte is that of Lang (Lang 1). The prothallia 

 which he describes were collected in part by himself in the Barrawa Reserve Forest 

 in Ceylon in March 1901. Other material studied by Lang was collected at the same 

 place by Mr. Coomara Swamy. I made a visit to the same locality in February 

 1906, and also found a considerable number of prothallia, but all of these had been 

 fertilized and had attached to them the young sporophyte, so that no young repro- 

 ductive organs were found. The forest where they were collected is subject to 

 inundation from a river which runs through it, and it was in the parts that had been 

 overflowed that the young plants were discovered. This makes it not unlikely that, 

 as in the case of Ophioglossum moluccanum, germination is favored by having the 

 spores immersed in water, and this may be a necessary condition for the first stages 

 of germination. 



A quantity of ripe spores were collected and various attempts were made to 

 germinate these, but without success, and, as none of the specimens obtained by 

 Lang were very young, the early history of the prothallium still remains to be 

 investigated. 



As in the other Ophioglossaceae, the prothallia are subterranean, occurring at a 

 depth of from 5 to 6 centimeters in the earth. In form (figs. 10, 11) they are some- 

 what intermediate between Botrychium and Ophioglossum, but are on the whole 

 more like the latter. They are somewhat irregular in outline, with a broad base, 

 recalling the basal tuber of 0. moluccanum, but this tuber is relatively larger and 

 more lobed. From this basal tuberous portion a short upright branch extends, 

 much as in Ophioglossum moluccanum, but it is relatively thicker and shorter. The 

 whole gametophyte is radial in structure, as in Ophioglossum, and thus differs 

 strikingly from the dorsiventral gametophyte of Botrychium. The basal enlarged 

 portion is brown in color and covered with rhizoids, which are mostly absent from 

 the upper, more slender part upon which the reproductive organs are borne. 



Lang found that there is a tendency to dicecism in the prothallia, some pro- 

 ducing only antheridia (figure 11, A), while in others archegonia predominate, 



