CHAPTER VI. 

 HORSETAILS AND CLUB MOSSES. 



HORSETAILS (EQUISETALES) 



Habitat. Equisetums or horsetails, a higher form of 

 plant life than the ferns, grow in moist or dry soil, depending 

 upon the species. 



Morphology of the Sporophyte. The sporophyte is differen- 

 tiated into a rhizome and one or two types of stems with or 

 without branches, depending upon the species, reduced scale- 

 like leaves and a strobile or cone-like spore-bearing part. 



The rhizome is composed of nodes and internodes. The 

 internodes are furrowed and blackish. The nodes are sur- 

 rounded by the adnate-toothed sheath of reduced leaves. 

 From the nodes develop branches and numerous whorls of 

 black fibrous roots which fix the plant firmly in the soil and 

 which serve as organs of absorption. 



In Equisetum arxense, the species illustrated, there are 

 sterile and fertile stems. 



The sterile stems and branches which develop after the 

 fertile stems, form the permanent or annual plant which is 

 seen growing in great numbers along railroad tracks and in 

 sandy fields. These sterile stems have furrowed internodes 

 and nodes with a whorl of reduced leaves adnate to form a 

 sheath whiclf is usually dark colored. No branches grow in 

 the axils of several of the sheaths immediately above the 

 ground. In the axils of the upper sheaths grow a whorl of 

 branches. The internodes of the branches are winged and 



