﻿290 BOTANICAL GAZETTE [April 



that in the gametophyte of the Ophioglossaceae there is an assemblage 

 of " filicinean " characters, which differ from those of Lycopodium itself. 

 But Celakovsky's comparison is with the lycoJ>ods- not with the germs 

 Lycopodium ; so far as the facts go, increasing ^^filicinean" characters of 

 the gametophyte follow in rough proportion to the larger size of the 

 leaf; thus from Isoetes we learn that a combination of cross-characters 

 is found in a megaphyllous lycopod type. What we find in the Ophio- 

 glossaceae is that in conjunction with their more pronounced mega- 

 phyllous form, still retaining, however, the lycopodinous type of the 

 sporophyte, they show more pronounced " filicinean " characters of the 

 gametophyte, and of the sexual organs. It is unfortunate that the facts 

 relating to the gametophyte of the Psilotaceae and Sphenophylleae are 

 not available in this comparison. 



It is not obvious what the meaning is of this parallelism between 

 leaf-size and characters of the sexual organs. A further difficulty in its 

 interpretation lies in the fact that for the Equiseta the parallelism 

 does not hold; there "filicinean" characters of the gametophyte 

 accompany entirely non-filicinean characters of the sporophyte, the 

 latter showing nearer analogy to the lycopods than to the ferns. Such 

 cross-characters are difficult to harmonize with any phylogenetic 

 theory; on account of them the Equisetineae are placed in an isolated 

 position, and in the same way, though with less pressing grounds, a 

 separate position should be accorded to those types which lie between 

 the extremes of lycopods and ferns, in proportion as the characters are 

 more or less pronounced. 



On this basis the Isoetaceae would probably best take their place as 

 a sub-series of the Lycopodiales, Ligulatae; the Psilotaceae and Spheno- 

 phylleae would constitute a series of Sphenophyllales, separate from, 

 but related to, the Lycopodiales. The Ophioglossaceae would form 

 an independent series of Ophioglossales more aloof than the latter 

 from the Lycopodiales, but not included in the Filicales. The actual 

 connection of these series by descent must remain open; it is quite 

 possible that some or all of them may have originated along distinct 

 lines from a general primitive group, which may beprovisionally desig- 

 nated the Protopteridophyta; these were probably small-leaved strobi- 

 loid forms with radial type of construction, and with the sporangia 

 disposed on some simple plan. The grouping arrived at in these 

 memoirs may be tabulated as follows : 



