Manchester Mefufliis, Vol. Ivi. (191 2), No. 12. 15 



that the most natural interpretation is one which 

 recognises an essential similarity in plan of stelar con- 

 struction between the Ophioglossaceae and the Coen- 

 opterideae. The origin of the vascular structure of the 

 Ophioglossace?e by elaboration of a protostele and devel- 

 opment of an intrastelar pith would have been parallel 

 to, but independent of, that in the Osmundacea-. When 

 the specialisation of the extinct groups and the imperfec- 

 tion of our knowledge regarding them is borne in mind it 

 seems inadvisable to suggest the direct derivation of the 

 Ophioglossaceje from any particular forms. It may be said, 

 however, that the Ophioglossaceai and Coenopterideae 

 appear to throw mutual light on one another as regards 

 morphology and anatomical structure, and that the 

 anatomical evidence supports the view that there is a real, 

 though it may be a collateral, relationship between the 

 two groups. 



