54 BASIS FOR SYSTEMATIC TREATMENT OF FERNS [CH. 



CLASS. FILICALES 

 Series i. FILICALES LEPTOSPORANGIATAE 



SUB-SERIES A. EUFILICINEAE 

 Faviily I. Hynienophyllaceae. (2 genera, 459 species.) 

 These are the typical "Filmy Ferns," relatively small, sometimes minute, 

 and mostly shade-loving. They were long regarded as the most primitive 

 of all Ferns, and related to the Mosses on account of their delicate structure. 

 Their sori are gradate, and the annulus oblique. 

 Faviily II. Cyatheaceae. (7 genera, 456 species.) 



Order i. Dicksonieae. 



Order ii. Thyrsopterideae. 



Order iii. Cyatheae. 

 These include the typical "Tree Ferns," with upright stems: their sori are 

 marginal or superficial, and gradate: the annulus is oblique. 

 Family III. Polypodiaceae. (i 14 genera, 4527 species.) 



Order i. Woodsieae. 



Order ii. Aspidieae. 



Order iii. Oleandreae. 



Order iv. Davallieae. 



Order v. Asplenieae. 



Order vi. Pterideae. 



Order vii. Vittarieae, 



Order viii. Polypodieae. 



Order ix. Acrosticheae. 

 These include the main bulk of the species of living Ferns: they are in fact 

 the dominant type of the present day: their sori are marginal or superficial, 

 and mixed, and the annulus vertical. 



Family IV. Parkeriaccae. (i genus, i species.) 

 A monotypic tropical family of specialised, semi-aquatic Ferns, with super- 

 ficial, solitary sporangia. 



Family V. Matoniaceae. (i genus, 2 species.) 

 A small tropical family, with only one living genus: probably a survival of 

 a type prevalent in Mesozoic times. Simple, superficial sori, sporangia with 

 oblique annulus. 



Family VI Gleidieniaceae. (2 genera, 80 species.) 

 Mostly straggling, tropical or sub-tropical Ferns, related to certain early 

 fossils; with superficial simple sorus, and primitive anatomy, sporangia with 

 oblique annulus. 



