THE EVOLUTION OF PLANTS 



605 



FIG. 426. Cycadeoidea ingens. Restoration of an expanded bispor- 

 angiate cone, or flower, in nearly longitudinal section. Restored from a 

 silicified fossil. (After Wieland.) 



FIG. 427. Cycadeoidea Dartoni. Tangential section through outer 

 tissues of the (fossilized) trunk, showing the very numerous seed-cones. 

 The seeds are very small (the illustration being natural size), and nearly 

 every one has a dicotyledonous embryo. There were over 500 such cones 

 on the original stem. (After a photograph loaned by Prof. Wieland.) 



