CHAPTER XXVI 



A GENERAL REVIEW OF THE SIMPLICES 



In the foregoing Chapters those Ferns have been examined which fall under 

 the designation of the Simplices. They have in common the feature that 

 the sporangia of each sorus originate simultaneously, and come to maturity 

 at approximately the same time. The sporangia are of relatively large size, 

 and each produces numerous spores. Since the sori borne on any individual 

 pinna, or even on a whole leaf, disclose only a slight acropetal succession 

 in the time of their appearance, the physiological drain for their nutrition is 

 practically simultaneous. This is regarded as a simple and primitive state as 

 compared with the more elaborate arrangements seen in other Ferns, by 

 which the demand for nutrition is spread over a long period. The Simplices 

 include all the living Eusporangiate Ferns, together with some others which 

 approach the Leptosporangiate state in the structure of their sporangia, 

 though these are not always referable in origin to a single parent cell, which 

 is the characteristic of that Sub-class. It is so with the Osmundaceae, 

 Schizaeaceae, Gleicheniaceae, and Matoniaceae, Families which occupy an 

 intermediate position between the Eusporangiate and the typical Leptospor- 

 angiate Ferns. 



It is significant that all the Families included thus within the Simplices, 

 with the exception of the Ophioglossaceae, have an early geological record. 

 The Coenopteridaceae, known only as fossils, are the characteristic Ferns of 

 the Palaeozoic Period. Ferns of the type of the Marattiaceae probably date 

 back to the Upper Carboniferous and the Permian Rocks, and are represented 

 in the Trias. The fossil Osmundaceae flourished from the Permian Period 

 onwards, while the Gleicheniaceae and Schizaeaceae, though their typical 

 features are strongly suggested by certain Palaeozoic fossils, undoubtedly 

 formed with the Matoniaceae a prominent constituent in Mesozoic Floras. 

 The only Family of the Simplices to which an early fossil history cannot be 

 ascribed by direct observation is the Ophioglossaceae. But the characters 

 which they bear leave little doubt that they are really related to other early 

 Fern-types, and in particular to the Botryopterideae. We are now able to 

 state on good palaeontological authority that "it is doubtful if the distinction 

 between the Eusporangiate and Leptosporangiate Ferns existed in Palaeo- 

 zoic times : — in other words, whether the development of the sporangium 

 from a single cell had yet been arrived at" (Scott, Stiidies, 3rd Edn. p. "i^GS). 

 Kidston has also expressed himself in very similar terms. When this result 

 is coupled with the positive existence of most of the types of the Simplices 

 in the Palaeozoic Period, there can be little doubt that we are right in recog- 



