PRESENT POSITION OF PALEOZOIC BOTANY—SCOTT. 385 
type. In this they differ strikingly from the seeds of the Pteropsida 
series, which even in the earhest known examples are already highly 
differentiated organs, with little trace of their Cryptogamie origin. 
Though there appears to be no sufficient evidence of any relation 
between the “ seed-bearing ” Lycopods and the higher plants, these 
curious fructifications are of great interest, for it is only in Lepido- 
carpon and Miadesmia, and, in a different way, in certain species of 
Selaginella at the present day, that we are able,-as it were, to observe 
a seed in statu nascendi. 
As regards the relation of Paleozoic to recent Lycopods, it seems 
most probable that the latter were derived, for the most part, from 
forms (perhaps such as Lycopodites) which have always been herba- 
ceous, rather than that they are the reduced descendents of arborescent 
Lepidodendrex. It is possible, however, that the Triassic genus 
Pleuromeia may represent a link between the latter group and the 
recent /soétes, which, of all the living Lycopods, appears to have most 
in common with the Lepidodendrex. 
THE SYSTEMATIC POSITION OF LYCOPSIDA. 
We have now to consider whether the classes grouped together in 
the Lycopsida really form a natural association, more nearly related 
among themselves than to outlying families of plants. So far as the 
Sphenophyllales and Equisetales are concerned, the affinities are clear 
and undoubted. We have also found reason to believe that, in a differ- 
ent direction, the Sphenophyllales show an affinity with the recent 
Psilotales. It is infortunate that we have as yet no certain knowledge 
of the geological history of the Psilotales themselves; it is not to be 
supposed that they sprang from the Sphenophyllales as actually 
known to us, but rather that the two groups had a common origin. 
The same remark applies to the Equisetales, which, though nearer to 
the Sphenophyllaceous type, can not have been derived from any of 
the specialized forms of which alone the remains have come down to 
us. The Sphenophyllales as represented in the Carboniferous Flora 
are best regarded as the last, highly modified, members of an ancient 
synthetic stock which in still earlier times appears to have had genetic 
relations to various other Pteridophytie phyla. The Devonian Pseu- 
dobornia, though at present placed in a class of its own, may well have 
belonged to the same main stock with the Sphenophyllales. 
The most difficult question is that of the relation of the Lyco- 
podiales to this phylum. Anatomically an affinity seems indicated, 
for the simpler protostelic Lycopods agree very nearly with the 
- Sphenophyllaceous type of stem structure as represented in Chezros- 
trobus. The verticillate arrangement of the appendages and their 
vascular strands scarcely causes any difficulty, for it frequently 
