34o STUDIES IN FOSSIL BOTANY 



really a Fern, while the analogies with Zygopteris and 

 other Botryopterideae are sufficiently close to justify us 

 in classing the whole family with the Ferns. I am 

 inclined to agree with the Messieurs Bertrand that the 

 affinity between Stauropteris and Zygopteris is a fairly 

 near one. At the same time, the absence of an 

 annulus from the sporangia of the former marks a 

 real distinction, though it will be remembered that 

 Diplolabis, a genus also betraying some affinity with 

 Zygopteris, has the same peculiarity. 



6. Affinities of the Family. — The habit, anatomy, and 

 sporangial characters all point to the Botryopterideae 

 having been true Ferns. The germinating spores of 

 Stauropteris, agreeing so closely with the corresponding 

 stages in recent homosporous Ferns, raise this pre- 

 sumption almost to a certainty, and there is at present 

 no countervailing evidence to be weighed. 



We have now to consider, very briefly, the question 

 of the probable affinities of the group with other 

 Filicales. 



The fructification, on which one would naturally 

 lay the chief stress, appears to remove the family from 

 any of the more typical groups of Leptosporangiate 

 Ferns. The size and form of the sporangia are too 

 variable to be characters of any importance, but the 

 annulus, when present, has definite peculiarities. In 

 the genera Zygopteris and Botryopteris it forms a well- 

 defined longitudinal or oblique multiseriate band of 

 cells, occurring on both sides of the sporangium in 

 Zygopteris, on one side only in Botryopteris. The 

 nearest analogy among recent Ferns is perhaps to be 



