216 The Palaeontological Record. II. Plants 



doubt homosporous Lycopods existed, but the great prevalence of 

 the higher mode of reproduction in days which to us appear ancient, 

 shows how long a course of evolution must have already been passed 

 through before the oldest known members of the group came into 

 being. The other characters of the Palaeozoic Lycopods tell the 

 same tale ; most of them attained the stature of trees, with a 

 corresponding elaboration of anatomical structure, and even the 

 herbaceous forms show no special simplicity. It appears from recent 

 work that herbaceous Lycopods, indistinguishable from our recent 

 Selaginellas, already existed in the time of the Coal-measures, while 

 one herbaceous form (Miadesmia) is known to have borne seeds. 



The utmost that can be said for primitiveness of character in 

 Palaeozoic Lycopods is that the anatomy of the stem, in its primary 

 ground-plan, as distinguished from its secondary growth, was simpler 

 than that of most Lycopodiums and Selaginellas at the present 

 day. There are also some peculiarities in the underground organs 

 (Stigmaria) which suggest the possibility of a somewhat imperfect 

 differentiation between root and stem, but precisely parallel difficulties 

 are met with in the case of the living Selaginellas, and in some degree 

 in species of Lycopodium. 



In spite of their high development in past ages the Lycopods, 

 recent and fossil, constitute, on the whole, a homogeneous group, 

 and there is little at present to connect them with other phyla. 

 Anatomically some relation to the Sphenophylls is indicated, and 

 perhaps the recent Psilotaceae give some support to this connection, 

 for while their nearest alliance appears to be with the Sphenophylls, 

 they approach the Lycopods in anatomy, habit, and mode of branching. 



The typically microphyllous character of the Lycopods, and the 

 simple relation between sporangium and sporophyll which obtains 

 throughout the class, have led various botanists to regard them as 

 the most primitive phylum of the Vascular Cryptogams. There is 

 nothing in the fossil record to disprove this view, but neither is there 

 anything to support it, for this class so far as we know is no more 

 ancient than the megaphyllous Cryptogams, and its earliest repre- 

 sentatives show no special simplicity. If the indications of affinity 

 with Sphenophylls are of any value the Lycopods are open to sus- 

 picion of reduction from a megaphyllous ancestry, but there is no 

 direct palaeontological evidence for such a history. 



The general conclusions to which we are led by a consideration 

 of the fossil record of the Vascular Cryptogams are still very hypo- 

 thetical, but may be provisionally stated as follows : 



The Ferns go back to the earliest known period. In Mesozoic 

 times practically all the existing families had appeared ; in the 

 Palaeozoic the class was less extensive than formerly believed, a 



