582 FILICALES 
first, that the latter are not marginal, excepting very occasional examples 
in O. palmatum, which is held as a derivative and outlying species; but 
secondly, the general comparison of characters, morphological and anatomical, 
of the sporophyte, of the sporangia, and of the gametophyte, indicates a quite 
separate position for the Ophioglossaceae. It suggests that the most that 
can be said is that some analogy exists between the Marsiliaceae ‘and 
Ophioglossaceae in the position of their spore-producing parts; but- the 
way in which this analogy has been attained is quite a different question. 
It seems probable that they represent quite distinct evolutionary sequences : 
a well-founded hypothesis has been stated above of an origin of the Ophio- 
glossaceous spike quite distinct from that of the sporocarp in the Marsiliaceae. 
