CHAPTER XXXVIII 
THE EVOLUTION OF PLANTS (Concluded) 
614. Evidences from Fossil Plants. The study of fossil 
plant remains has greatly enlarged our knowledge of 
the course of plant evolution, filling in gaps derived from 
the study of living forms, and affording new facts, not 
disclosed by the study of plants now living. Like the 
study of comparative anatomy and life histories, paleo- 
botany teaches us that there has been a gradual evolu- 
tionary progress from the simple to the more complex, but 
it has also disclosed the fact that some of the complex 
forms are much more ancient than had been inferred from 
the study of living plants only. 
615. Discovery of Seed-bearing Ferns. For example, 
remains of seed-bearing plants, quite as highly organized 
as those of to-day, are found far back in the earliest fossil- 
bearing strata of the Paleozoic. Great forest types ex- 
isted as early as the Devonian. Later in the Carboniferous 
occur many seed-bearing ferns. These have been 
called Cycadofilicales (cycadaceous ferns), or, by some, 
Pterido sperms. Recent studies have disclosed the fact 
that most of the fossil plants from the Carboniferous coal- 
bearing strata, formerly thought to be ferns, are not even 
cryptogams, but are these fern-like seed-bearing plants. 
The best known pteridosperm is Lyginodendron oldhamium 
(Fig. 415), first described from fossil leaves, in 1829, as 
a tree-fern, under the name Sphenopteris Hoeninghausi. 
592 
