Pteridophyten. 199 



bearing sporangia on the cotylcdon and as stemless, which latter 

 feature is the early condition of O. moluccanum. The resemblance 

 of Anthoceros to the ferns in the "imbedded" sex-organs is another 

 notable feature, which has long been recognized. The greatest dis- 

 similarity is pointed out to be in the structure of the sperms, which 

 demand the most extensive changes in passing from Anthoceros to 

 Ophioglossum. It is claimed that the subterranian, saprophytic 

 gatnetophyte of Ophioglossum is, without doubt, a secondary con- 

 dition, derived from some such gatnetophyte as that of the Marattiaceae 

 by entering into symbiotic relationship with an endophytic fungus. 



The arguments used to associate Ophioglossaceae and Marattia- 

 ceae in a common origin are numerous, the principal ones being 

 as follows. The short-necked archegonium is characteristic of both, 

 and is more primitive than long-necked archegonia (such as appear 

 in Botrychium), because the necks in ferns come from the four 

 terminal cells of the neck in Bryophytes, and thercfore the forms 

 with shortest necks approach most nearly the ancestral type in 

 this feature. The question of the canal cells is acknowledged to be 

 a puzzling one, for in Ophioglossum and Danaea there is a dege- 

 nerate ventral canal cell, and in the less primitive forms this cell 

 is not degenerate. The general similarity of the condition of the 

 canal cells in the plexus as a whole, however, is evident. The per- 

 sistent monophyllous condition of the Ophioglossaceae is regarded 

 as primitive, and therefore such a body could not be regarded as 

 a strobilus. Among the Marattiaceae, Kaulfussia approaches this 

 condition most nearly, the older plants having only two or three 

 leaves and frequently only one. 



The embryo of O. moluccanum is emphasized as most nearly 

 representing the hypothetical "pro-ferns", and its vascular structure 

 is described in detail. For a considerable time in the ontogeny of 

 this plant, the vascular System is said to consist only of the vascular 

 Strands of roots and leaves, the stem apex playing no part in buil- 

 ding up the vascular framework. "The idea that there is a special 

 stem stele, of which root traces and leaf traces are subsidiary struc- 

 tures is not borne out". The Single, axial, collateral Strand through 

 cotyledon and root is said to be the starting point of two types of 

 vascular skleton: 1) as in Ophioglossum, in which there is a cylin- 

 drical network ^with wide meshes) of collateral leaf traces, becoming 

 more complicated in the Marattiaceae (due to the larger leaves), 

 and in which the collateral bundles are replaced by concentric ones; 

 and 2) as in Botrychium, in which there is a compact, hollow cy- 

 linder, formed by the complete union of broad leaf traces. 



The principal general conclusions are that from some form 

 allied to the simpler species of Ophioglossum the wole fern series 

 is descended; that in this series the leaf is the predominating organ, 

 the stem at first being quite subordinate; that the ancestral fern 

 was monophyllous and the leaf at first a sporophyll; that from this 

 "central type" several lines diverged (one being represented by Bei- 

 minthostachys and Botrychium , with their saprophytic gatnetophyte; 

 the other by the Marattiaceae, which are probably not a Single line 

 of descent); that Helminthostachys is probably the point of contact 

 between Ophioglossaceae and Marattiaceae; that among Marattiaceae, 

 Kaulfussia is most primitive and Angiopteris most specialized; and 

 that the Marattiaceae are nearer the leptosporangiate ferns than are 

 the Ophioglossaceae and have probably given rise to them. 



Coulter (Chicago). 



