348 STUDIES IN FOSSIL BOTANY 



It is doubtful if the distinction between Euspor- 

 angiate and Leptosporangiate Ferns existed in 

 Palaeozoic times — in other , words, whether the de- 

 velopment of the sporangium from a single cell 

 had yet been arrived at. In the Botryopterideae, 

 at any rate, it is improbable that this was the case, 

 the mode of insertion of the sporangia, and their 

 large size in many cases, pointing to a multicellular 

 origin. 



The conclusions of Professors Campbell and Bower, 

 as to the relative antiquity of the Eusporangiate type, 

 are thus amply justified by palasontological evidence. 

 On the other hand, it may be doubted whether this 

 evidence justifies the view that the confluent synangium 

 was a primitive form of Fern -fructification. Many 

 Palaeozoic Marattiaceae, it is true, possessed synangia, 

 but, on the whole, the sporangia of which they were 

 composed were less completely united than in most of 

 the recent members of the family. While in Ptycho- 

 carpus the cohesion was complete, in Scolecopteris, 

 Asterotheca, Sturiella, and the GrancPEurya of Stur 

 the individual sporangia enjoyed a considerable measure 

 of independence. Neither were the Marattiaceae by any 

 means the most ancient Ferns. The Botryopterideae 

 were older, and had, in most cases, free sporangia. 

 Among the fairly numerous Fern-sporangia preserved 

 in the petrified material of the British Lower Coal- 

 measures and Lower Carboniferous rocks, it is rare 

 to find any signs of cohesion. The fossil evidence, 

 on the whole, supports the view that free sporangia 

 represent the original form of Filicinean fructifica- 

 tion, and that their cohesion to form synangia was 



