GENEEAL MORPHOLOGY OP THE PLANT 7 



Still ascending, we find in the Perns {fig. 13), Horsetails 

 [fig. 12), Pepperworts, Club-mosses [fig. 11), and Selaginellas 

 a pontinued advance in complexity of structure; vessels of 

 different kinds make their appearance, and the stems are fre- 

 quently of considerable size and height. Calamites, an order of 



FrR. 10. 



Ficj. 11. 



Fie. 12. 



Fig. 9. Plant of tlie Haii--moss i,Poly- 

 trichurn co}nmn?ie), i\'ith leaves, stem, 



and sporogouium. F/ff. 11). Plant 



of the same, with stem and leaves, 

 and terminated by the male organs 



('iti/heriiJia). Fiff. 11. The common 



Clnb-moss (.Lycopodii'in' davdium) 



Fig, 12. Termination; of fertile 



branch of the Great Water Horsetail 

 {Equisetiim maximum). 



extinct plants allied to the Horsetails, which were extremely 

 abundant during the formation of our coal measures, appear to 

 have reached the height of our loftiest trees ; while at the 

 present day in the tropics and warmer parts of the earth 

 Perns frequently attain the height of twenty feet {fig. 14), and 



