86 



THE OPHIOGLOSSALES 



THE SPOROPHYTE OF OPHIOGLOSSUM. 



Of the three existing genera of the Ophioglossaceae, the genus Ophioglossum 

 is much the largest and most widespread. The number of species, however, is very 

 imperfectly understood, as there is great confusion in the nomenclature, owing to 



the inadequate study of the tropical species, of which 

 the number is undoubtedly much greater than has 

 generally been supposed. The smaller terrestrial species 

 look very much alike and it is evident that collectors have 

 often failed to discriminate among them. My attention 

 was especially called to this while I was collecting ma- 

 terial of Ophioglossum in Java, where there is evidently 

 a considerable number of species. Raciborski (Raci- 

 borski 1), who has described the Pteridophytes of this 

 region, mentions only a single species as occurring in the 

 neighborhood of Buitenzorg, where most of my collect- 

 ing was done. But in that immediate neighborhood 1 

 collected at least three very distinct species, and two 

 were collected at Tjibodas, some 4,000 feet above Buit- 

 enzorg. Raciborski, however, mentions only a single 

 species as occurring at Tjibodas. There is no doubt 

 that a critical study of these plants from other regions 

 where they abound will greatly increase the number of 

 species to be recorded. 



The great majority of the species of Ophioglossum 

 belong to the subgenus Euophtoglossum, which should 

 probably be separated completely from the very differ- 

 ent forms which comprise the other subgenera. The 

 species of Euophtoglossum are all small or moderate- 

 sized plants with undivided leaves which are generally 

 lanceolate or broadly oval in outline and have the 

 sporangial spike borne on a very long stalk attached to 

 the sterile part of the leaf near the base of the lamina. 

 These plants are always terrestrial, the leaves growing 

 from an upright rhizome, which is sometimes a good 

 deal enlarged, sometimes more slender in form. From 

 the rhizome there extend numerous roots which are 

 sometimes developed one for each leaf, but this is by 

 no means always the case. The sporophyte of Euophto- 

 glossum seldom exceeds a height of 30 to 40 centime- 

 ters and some of them are very much smaller (fig. 55, 

 also plate 3). 



Except for their larger size the later leaves do not 

 differ essentially from the primary leaf of the young 

 sporophyte. The venation is always reticulate, usually 

 without any definite midrib, although sometimes there is a central vein which is 

 slightly stronger than the others. In many species, e. g., 0. moluccanum, 0. vulga- 

 tum, small branches ending blindly are found within the large meshes. In other 

 species, e. g., 0. lusitantcum, there are no free veins within the areoles. 



In many of the species but one leaf is formed each year, but in others, especially 

 many of the tropical species, there may be as many as four or five formed in a 



Fig. 55. 



Two specimens of Ophioglossum moluc- 

 canum (Schlecht), slighdy reduced. 

 The larger one is the typical 0. 

 moluccanum ; the smaller one is 

 probably a second species. 



