Ill] A CURRENT CLASSIFICATION 



55 



Family VII. Schizaeaceae. (4 genera, 118 species.) 

 Ferns of varied habit and structure, but all with relatively simple sori, 

 monangial, and typically marginal: related to certain early fossils. Annulus 

 distal and almost transverse. 



Family VIII. Osmwidaceae. (3 genera, 17 species.) 

 This is the family of the Royal Fern. The habit, anatomy, and the large 

 sporangia suggest a primitive type, related to certain early fossils. Some 

 of them are "Filmy." 



SUB-SERIES B. HYDROPTERIDINEAE 

 Family IX. Salviniaceae. (2 genera, 18 species.) 

 Floating Ferns of small size and simple structure, with sexually distinct 

 sporangia. 



Family X. Marsiliaceae. (3 genera, 63 species.) 

 Ferns of aquatic habit, whose relatively simple structure links on to more 

 complex types. They also have sexually distinct sporangia. 



Series 2. MARATTIALES 



Family XI. Marattiaceae. (5 genera, 118 species.) 

 Sappy tropical Ferns often of large size, with leathery leaves and simple 

 sori, and sporangia of large size. Their characters appear to be primitive, 

 but Cycad-like. They are related to certain early fossils. 



Series 3. OPHIOGLOSSALES 



Family XII. Ophioglossaceae. (3 genera, 78 species.) 

 The Moonworts and Adder's Tongues, with very peculiar habit. The large 

 sporangia are borne on a "fertile spike." Prothalli typically subterranean. 



It may not have been the intention of Engler and Prantl, or of Christensen, 

 to express in this arrangement any definite opinion as to the relationship 

 of the several Families. Certainly the sequence as shown does not accord 

 with any probable phyletic view as checked by palaeontological evidence. 

 It will not be necessary here to enter on a detailed criticism of it. It must 

 suffice to note a few examples which' show the sort of discrepancies that 

 exist in it. The Hymenophyllaceae are placed first in accordance with a 

 common practice of many of the older writers, though these Ferns cannot 

 now be held to be either the most primitive or the most advanced types of 

 Ferns. The Hydropterideae are spliced between the Osmundaceae and the 

 Marattiaceae, though they show no near affinity with either. Dipteris is 

 placed in the Aspidieae (III. ii) far away from its relative Platycerium, which 



