The Origin of Land Plants 85 



the so-called " vascular " plants, the ferns and flow- 

 ering plants. 



The First Land Plants Allied to Liverworts. 

 Certain liverworts probably resemble pretty closely 

 the first land plants. These are small plants of very 

 simple structure, lying flat upon the ground, to 

 which they are attached by delicate roots. Struc- 

 turally these liverworts are some of them less 

 complex than many of the algae, often being com- 

 posed of almost perfectly uniform cells. They show 



FIG. 8 



A A simple liverwort, Ricciocarpus, showing the small 

 globular sporophytes, sp, imbedded in the thallus. 



B A large liverwort, Treubia, having leaf-like organs; the 

 sporophyte has a long stalk or seta, carrying up the terminal 

 spore-bearing capsule. 



certain resemblances to some of the simple algae, 

 especially the order known as the Ulothricales, 

 which on the whole come nearer to the liverworts 

 than do any other algse. It must be admitted, how- 



