EVOLUTION OF SEED-PLANTS 119 



juxtaposition of the organs to form a flower, 

 and the complex gynseceuni with its reduced 

 carpels are new characters, the origin of which 

 still remains to be cleared up. 



We happen to have but few plant-fossils from 

 the Upper Permian or Lower Triassic rocks, and 

 these blank pages of the geological history may 

 account for the gap in OUT knowledge. Cycado- 

 phyta had begun to be evolved before the close 

 of the Palaeozoic period, but we know little of 

 their fructification, and there is nothing to indi- 

 cate any approach to the Bennettitean type. 

 We may, however, mention here an extraordi- 

 nary genus, Doleropkyllum, from the Upper Coal 

 Measures and Permian of France and Russia, 

 as an example of a quite peculiar early type of 

 Cycadophyte. 



The leaves were simple and round in outline, 

 sometimes eight inches across; huge buds have 

 been found, containing the young, unexpanded 

 leaves. The structure of the vascular strands 

 agrees exactly with that in the leaves of Cycads. 

 Associated with the foliage-leaves, smaller discs 

 have been found which have proved to be the 

 stamens. These discs are very thick and con- 

 tain a number of cylindrical chambers, placed 

 vertically to the surface and filled with pollen- 

 grains of large size and complex structure. Each 

 grain was multicellular and opened by a lid. 



