640 STUDIES IN FOSSIL BOTANY 



detected lying in the fructification and in the occurrence 

 of reticulated tracheides. He regarded the Botryopteri- 

 deae as intermediate in stem and fructification between 

 the Hymenophyllaceae, representing the Ferns properly 

 so-called, and the distinct group Ophioglossaceae ] — a 

 view for which there is still much to be said. The 

 sporangia of Stauropteris (a genus not known to 

 Renault) present an almost exact agreement with those 

 of Bottychium, as regards their structure and the mode 

 of attachment by vascular pedicels. 2 The resemblance 

 in the structure of the tracheides has proved to be 

 even more striking than Renault was aware, for true 

 pitted tracheides of a " Gymnospermous " type occur in 

 both groups. It may be added that the structure of 

 the stem in the new Botryopteridean genus Botrychi- 

 oxylon (p. 3 1 8) if it lost the internal wood (a change likely 

 to occur, from the analogy of parallel cases elsewhere 3 ) 

 would be almost exactly that of a Botrychium. The 

 fact that the frond (at least the fertile frond) of 

 certain Botryopterids branched in more than one plane 

 has been compared with the dorsiventral branching of 

 the frond characteristic of Ophioglossaceae. 4 



On the whole, a real affinity between the fossil and 

 the recent family seems probable — in fact, of known 

 plants, it is the Botryopterideae which appear to have 

 most in common with the Ophioglossaceae. 



Professor Bower thinks it " probable that the 



1 B. Renault, Veg&aux silicifies d'Autun, etc., Autun, 1878, p. 114. 

 "In Botrychium they are short, in this respect resembling those of 

 Bolryopteris. 



3 See below, p. 651. 



4 Lady Isabel Browne, " Phylogeny and Inter-relationships of Pterido- 

 phyta, vi. Filicales," New Phytologist, vol. vii. 1909, p. 27. 



