146 D. H. Scott. 



VASCULARES. 



Tlie land veg-etation of the Palaeozoic period, from the Devonian 

 onwards, was in part Pteridophytic and in part Spermophytic. In the 

 light of our present knowledge it appears probable that in the Car- 

 boniferous, at all events, the latter element was predominant, and 

 possibly this may already have been the case even in Devonian 

 times. The conception of the Palaeozoic age as the Reign of the 

 Cryptogams, current from the time of its author Brongniart down 

 to our own day, has lost its validity, owing to the increasing evidence 

 for the seed-bearing character of a large proportion of the forms 

 hitherto classed as Cryptogamic. The Spermophyta of the Palaeozoic 

 period consisted on the one hand of well-characterized Gymnosperms, 

 and on the other of a great assemblage of Fern-like forms, resembling 

 the contemporary Gymnosperms as regards their seeds, but separated 

 from them by the primitive character of their general organization; 

 they may be treated as a distinct class — the Pteridospermeae. In 

 addition to Gymnosperms and Pteridosperms, the ranks of Palaeozoic 

 •'seed-bearing plants*' were further recruited from a diiferent source, 

 the Lycopodiales, some members of which, as recent investigation has 

 shown, had made a great advance in the Spermophytic direction, 

 producing organs closely analogous with true seeds. 



The division of vascular plants into Spermophyta and Pterido- 

 phyta, though sanctioned by botanical usage, ceases to affoi'd a natural 

 line of cleavage wlien we are concerned with Palaeozoic vegetation. 

 A large proportion of the seed-plants of that period, were, until 

 recently, classed as Ferns, and though their position has changed 

 there is no doubt that the affinity between the Pteridosperms, as we 

 now call them, and the Ferns, was far closer than that between the 

 Ferns and any other known group of Pteridophyta. Further, the 

 Lycopods above referred to, which were reproduced by means of 

 seed-like organs, were in all other respects as true Lycopods as any 

 of their purely Cryptogamic allies. 



Hence we hav.e to seek some other line of separation, if w'e wish, 

 on grounds of convenience, to group the Palaeozoic Yasculares under 

 two main divisions. 



As a provisional scheme, we may adopt Prof. Jeffrey's proposed 

 division of the Vascular Plants into Lycopsida and Pteropsida ^), the 

 former including Sphenophyllales (as here limited, a wholly Palaeozoic 

 class) Equisetales and Lycopodiales, while the latter embrace the 

 Filicales and the whole of the Flowering Plants. 



^) E. C. Jeffrey, Morphology of Central Cylinder in Angiosperms. Trans. 

 Canadian Institute, p. 36, 1900; Structure and Development of Stem in Pteridophyta 

 and Gymnosperms. Phil. Trans. Eoyal Soc. B., Vol. 195 p. 144. 1902. 



