THE HORSETAIL FAMILY. 



485 



CLIV.— THE HORSETAIL FAMILY. Equisetdcece. 



A family consisting of a single genus of perhaps not more than ten 

 species, but widely dispersed over the world, and almost the whole 

 copiously represented in our own country. The stems are erect, rush- 

 like, cylindrical, hollow, jointed, more or less deeply furrowed, gene- 

 rally rigid, perfectly glabrous, though often rough, and of heights 

 varying from twelve inches to five or six feet. At every joint there is 



Fig. 213. 



Fig. 212. Field Horsetail. 



Sylvan Horsetail. 



a membranous sheath, half an inch to an inch or more in length, 

 enclosing the base of the internode next above it, and fringed or 

 toothed at the upper edge. No leaves are developed, but in general 

 abundance of long, thin, slender, and almost hair-like branches, which 

 spread in regular whorls from the joints of the stem. The branches 

 are sometimes a little compound, usually quite simple, and in a 

 few cases altogether absent. When a slightly- withered stem of 



