584 MOSSES AND FERNS chap. 



rangiate Ferns during the Palaeozoic, none of these forms are 

 beyond dispute. That there were Ferns whose sporangia pos- 

 sessed a well-marked annulus seems certain, but the character 

 of these sporangia is somewhat doubtful. Of forms perhaps 

 allied to the Gleicheniacese, may be mentioned the genus Oligo- 

 carpia (Scott (i). Fig. 92). Sporangia have also been found 

 with a transverse annulus not unlike that of the Hymenophyl- 

 laceae, and described as Hymenophyllites, and not infrequently 

 sporangia are encountered which suggest the Osmundacese, and 

 there is also evidence for the existence of forms allied to the 

 Schizgeaceae. 



While the Marattiacese were still predominant at the begin- 

 ning of the Mesozoic, by the time the Jurassic formations are 

 encountered, they are largely replaced by the lower leptospo- 

 rangiate Ferns. Osmundacese and Cyatheacese appear to have 

 been the predominant families at this period ( Scott ( i ) , p. 

 304). There were also Schizseacese, Gleicheniaceas, and per- 

 haps Hymenophyllaceae, but no true Polypodiacese have been 

 found in the earlier Mesozoic formations. 



A characteristic family of the Mesozoic is that of the Ma- 

 toniacese, which combines characters of the Gleicheniacese and 

 Cyatheaceae and was represented by very many forms. At 

 present only two species of Matonia survive, rare Ferns of the 

 Malayan region. 



The Polypodiacese first appear in the later secondary for- 

 mations, and from that time have formed the prevailing Fern 

 type. 



The remains of the Hydropterides, the heterosporous 

 Ferns, are too meagre and uncertain to throw much light upon 

 their origin. 



Cycadofilices {Scott (i), Potonie (j)) 



One of the most important results of the work of Palse- 

 botanists during the last decade has been the discovery that 

 many of the supposed Ferns of the Palaeozoic were really forms 

 which were intermediate between the true Ferns and Cycads, 

 and hence they have very appropriately been named Cycado- 

 filices. Some of the Cycadofilices were evidently nearer to the 

 Ferns than to the Cycads. Of these may be cited the genera 

 Lyginodendron and Heterangium, which have been very fully 



