140 FERNS AND THEIR ALLIES 



slender than the fertile stems, with the whorls 

 more numerous. 



It grows in moist, shady places, and is com- 

 mon in northern New England. 



SCOURING-RUSH. 



Equisetum liyeinak. 



Stems all simple, hollow, grooved, and from 

 one to three feet high. Sheaths short, the teeth 

 blackish and soon disappearing. 



This species is common in northern New 

 England, growing in wet places and. along the 

 banks of streams. It was formerly used for 

 polishing wood and metal, its roughness being 

 due to the silex in its composition. The stems 

 are evergreen. 



The fertile spike at the summit is ovoid and 

 matures in June and July. 



FIELD HORSETAIL. 



Equiseium arvense. 



The fertile stems appear first. They are from 

 four to ten inches high, a light, delicate brown 

 in color, soft, with large, distant, coarsely 

 toothed, inflated sheaths ; they terminate in a 

 spike one inch long. These stems soon wither 

 and are followed by the taller, herbaceous, green, 

 sterile stems which produce whorls of upright 

 branches. These are sometimes simple, but 



