632 STUDIES IN FOSSIL BOTANY 



Professor Lignier, 1 on the other hand, while regarding 

 the synangium as a terminal spikelet, takes the view 

 that the Psilotales are excessively primitive, being the 

 nearest living representatives of his hypothetical pro- 

 Lycopod type, which he supposes to have formed the 

 starting-point of the Vascular Plants. I cannot accept 

 the epiphytic group Psilotales as really primitive, for 

 one of the two genera bears obvious marks of reduction 

 in relation to habitat, while the other shows signs of 

 modification in the same direction, though in a lesser 

 degree. Neither is there any satisfactory geological 

 evidence for the antiquity of the family in its present 

 form. 



Lycopsida 



On the whole the fossil record as yet throws singu- 

 larly little light on the origin and affinities of the 

 Lycopodiales. In the first edition of these " Studies " I 

 laid stress on the relation of this class to the Spheno- 

 phyllales, and, through them, to the Equisetales. Pro- 

 fessor Jeffrey, on independent grounds, united all these 

 classes in his Lycopsida, 2 as a main division of Vascular 

 Plants, while his Pteropsida included all the remaining 

 groups. It now appears probable that the Articulatae 

 were derived from megaphyllous plants, whereas we 

 have at present no evidence that the Lycopods were ever 

 anything but microphyllous, though the possibility of 

 a reduction from large-leaved forms remains open. 

 Further, the Articulatae and Psilotales are " sporangio- 



1 See his two papers cited above, p. 615. 



2 E. C. Jeffrey, " Structure and Development of the Stem in the Pteri- 

 dophyta and Gymnosperms," Phil. Trans. Royal Soc. B, vol. 195 1902 

 p. 144 ; also his earlier papers there cited. 



