6 THE OPHIOGLOSSALES 



may arise close to the base of the petiole and appear to be quite independent of 

 the sterile leaf segment. The sporangia range in number from about half a dozen, 

 in some of the smaller forms of Botrychium simplex and Ophioglossum, to many 

 hundred in such large species as Botrychium virginianum and Helminthostachys. 

 There is a most interesting series of forms connecting the smaller and simpler types 

 with the large and complicated ones. With the increasing complexity of the sporan- 

 giophores, there is usually a reduction in the size of the sporangia, which, however, 

 become better differentiated than in the simpler types. 



There is no question about the close relationships existing between the dif- 

 ferent genera of the Ophioglossaceae, but there is some difference of opinion as to 

 their connection with other Pteridophytes. While they are probably sufficiently 

 distinct to be relegated to a special order, Ophioglossales, their peculiarities hardly 

 warrant separating them entirely from the ferns. As will be seen later, they offer 

 many points of resemblance to the Marattiales, both in regard to the structure of 

 the adult sporophyte and that of the gametophyte or sexual plant, and the early 

 phases of embryonic development. These resemblances are too numerous and too 

 exact to make it at all likely that the two orders are unrelated. 



I. THE GAMETOPHYTE. 



The first discovery of the gametophyte of the Ophioglossaceae was made by 

 Hofmeister (Hofmeister 1) who, in 1854, found the gametophyte of Botrychium 

 lunaria; two years later Mettenius (Mettenius I) described much more fully the 

 prothallium of Ophioglossum pedunculosum, which was cultivated in the botanical 

 garden at Leipzig. No further additions were made to the subject until the writer 

 (Campbell 4) succeeded in obtaining the first germinating stages of O. pendulum, 

 collected in the Hawaiian Islands, and those of Botrychium virginianum; and the 

 older gametophyte of the latter species was also described. In the year 1898 Jeffrey 

 (Jeffrey 1) published a complete account of the gametophyte and embryo of Bo- 

 trychium virginianum. Later contributions to the subject are those of Lang 

 (Lang 1) on the gametophyte oi Ophioglossum pendulum and oi Helminthostachys; 

 and the papers of Bruchmann (Bruchmann 1, 2) on the prothallium of Botrychium 

 lunaria and Ophioglossum vulgatum. In 1905, Lyon (Lyon 1) published a brief 

 account of the embryo of Botrychium obliquum. 



In 1906 I collected in Ceylon a few prothallia of a species of Ophioglossum 

 which may have been 0. reticulatum, and shortly afterward, during a stay in Java, 

 a number of prothallia of 0. moluccanum were found, as well as a few belonging to 

 an undetermined species associated with the latter. During my stay in Java I was 

 fortunate enough to obtain also a large number of prothallia of 0. pendulum. An 

 account of these has already been published (Campbell 8). 



All species of the Ophioglossaceae that have yet been examined agree in the 

 underground habit and saprophytic nature of the gametophyte, which always has 

 associated with it a peculiar endophytic fungus, or " mycorrhiza," which is un- 

 doubtedly connected with the assimilation of organic food. Mettenius states that 

 chlorophyll may be developed if the prothallium appears above ground, and Bruch- 

 mann found that this was also true in O. vulgatum; but as a rule the prothallium 

 remains subterranean and quite destitute of chlorophyll. 



The spores of the Ophioglossaceas are always of the tetrahedral type, and when 

 ripe possess a moderately thick sculptured outer membrane, which is usually colorless 

 or pale yellow, so that the masses of spores are either white or a pale sulphur-yellow 

 tint. The ripe spore as a rule is packed with granular matter, which makes the 



