498 



FILICALES 



are the dominant Ferns of the present day, while the Gradatae take a j 

 middle place. This succession will be maintained in the detailed account < 

 of the several families, and consequently the description will follow in 

 the main, though not in exact detail, the order of appearance of the 

 several families of Homosporous Ferns upon the earth's surface. The 

 order in which they will be taken up will be as follows : 



Simplices < 



Botryopterideae. 



Marattiaceae (together with many Pecopterids). 

 Osmundaceae. 



Schizaeaceae [Marsiliaceae] ? 

 Gleicheniaceae. 

 ^Matonineae. 



fLoxsomaceae. 



Hymenophyllaceae. 

 Gradatae { Dicksonieae (excluding certain genera). 



Dennstaedtiinae. 

 ^.Cyatheaceae [Salviniaceae] ? 



IDennstaedtia-Davallia series. ' 

 Onoclea-Woodsia series. 

 Matonia-Dipteris series. 

 Pterideae and other Polypodiaceae 



Mixtae 



BOTRYOPTERIDEAK. 1 



The organisms grouped under this name occur as Palaeozoic fossils 

 extending upwards to the Permian. 2 Though they are distinct frorr 

 any other known family of Ferns, still there is no reason to doubt theii 

 Fern-nature : its recognition is based not only upon the external characters 

 of the shoot, with the usual circinate vernation of the leaves, but als( 

 upon the anatomical details of axis and leaf, and upon the fact that tl 

 numerous sporangia are borne upon the distal region of the repeatec 

 pinnate sporophylls. Finally, in Stauropteris Oldhamia Scott has sh<N 

 that the spores possessed the capacity for germination within 

 sporangium, as in some modern Ferns. 



The plants had an erect shoot of radial construction : it was sometii 

 short, with closely aggregated leaves, as in Grammatopteris RigolL 



1 The materials for this description have been derived in the main from Rena 

 Bassin Houiller et Permien d'Autnn et d'Epinac, ii., p. 33, etc. ; Scott, Studies, p. 

 etc. ; Stenzel, Bibliotheca Botanica, 1889, No. 12 ; Scott, Progresses Rei. Bot., i., p. i 

 I have also had the advantage of comparing specimens, chiefly those belonging to 

 Kidston. 



-Mr. Kidston has shown me a Botryopterid (B. antiijna) from the Petticur P>ed 

 with axis and leaf bases showing structure. This he reg;uds as probably the earlie 

 record of a Botryopleris. 





