22 THE OPHIOGLOSSALES 



the granular appearance disappears to a considerable extent, though the nuclei 

 continue to stain strongly. The fungus is quite variable in form. Sometimes the 

 filaments are nearly straight, running from cell to cell and branching sparingly. 

 Sometimes a cell is completely filled with a dense tangle of hyphae, while in other 

 cases there are sack-like vesicles of very irregular form. Not infrequently, quite 

 regular, nearly globular bodies are seen, recalling the oogonia of the Peronosporeae. 

 These at first contain comparatively few nuclei, scattered through the granular 

 cytoplasm, but in the older ones the nuclei are very numerous and decidedly larger. 

 It looks sometimes as if this were a preparation for the formation of spores, but no 

 certain evidence of the formation of such spores could be seen, although in several 

 instances there was an appearance which might point to this. Structures resembling 

 the "conidia," described by Jeffrey for Botrychium (Jeffrey 1, page 12), were seen 

 and are probably the same thing. 



As the fungus invades the young cells, irregular, strongly-staining clumps are 

 formed by the aggregation and breaking down of the starch grains. The nucleus 

 of the host cell appears to be but slightly affected by the growth of the fungus, and 

 can usually be found quite unchanged, even in those cells which are almost com- 

 pletely filled by the endophyte. Finally, the thin-walled vesicular growths of the 

 fungus are quite broken down and probably serve to nourish the cells of the gameto- 

 phyte, which is thus parasitic upon the cells of the fungus. The systematic position 

 of the fungus is doubtful. The varicose, swollen hyphae found at certain stages 

 closely resemble a parasitic fungus, Completoria complens, which is sometimes 

 extremely destructive to green fern prothallia. The obgonium-like organs, often 

 present, suggest Pythium, a parasitic fungus belonging to the Peronosporeae. 

 Jeffrey (Jeffrey 1, page 13) thinks the endophyte may fairly be regarded as an 

 intermediate form between the two genera, Completoria and Pythium, and says that 

 in this case Completoria should be placed in the Peronosporeae instead of in the 

 Entomophthoreae, where it has been placed by some students of the Fungi. 



THE SEXUAL ORGANS. 



THE AXTHERIDIL'M 



The antheridium in all of the Ophioglossaceae is of much the same type and 

 closely resembles that of the Marattiaceae and also Equisetum and Lycopodium. 

 The mother cell does not project at all above the level of the adjacent tissue, and in 

 all cases the first division separates a superficial or cover cell from an inner one, the 

 latter by further divisions giving rise to a mass of sperm cells which may be very 

 numerous. The cover cell also divides, sometimes only in one plan, sometimes 

 (e. g., in Botrychium) having also periclinal divisions. At maturity the antheridium 

 may project more or less strongly, but this is not always the case. 



THE ANTHERIDIUM OF OPHIOGLOSSUM 



The antheridium was first described by Mettenius in Ophioglossum pedunculo- 

 sum, and later Lang described it for O. pendulum and Bruchmann for 0. vulgatum. 

 The present account is based mainly upon my own studies of 0. moluccanum and 

 O. pendulum. 



The mother cell of the antheridium, which may arise very close to the growing 

 point of the prothallium, lies flush with the neighboring cells, but later it may 

 become more or less elevated above the surface, forming a prominence which, in 

 slender prothallia, like those of Ophioglossum moluccanum, may give an irregular 

 undulate outline to the branch which bears them (fig. 4, A). In O. pendulum 



