HORSETAIL FAMILY 143 



often produce at each joint a whorl of ascend- 

 ing, four-angled branches, few in number. 



Field Horsetail is found along railways, also 

 in moist, gravelly or sandy soil, and is fre- 

 quently a companion of the Sensitive Fern, 

 wrongly called the "Polypod." Various other 

 names for it are in use, such as Meadow Pine, 

 Foxtail, Jointed Rush, and Colt's Tail. It is 

 poisonous to horses, producing a fatal malady if 

 its use is long continued. 



The fruit matures in April and May. 



PIPES. 



Eqiiisetwn limosum {E. fluviatile). 



The stems are all similar, slightly furrowed, 

 and usually produce after fruiting from two to 

 six whorls of slender, ascending branches near 

 the middle. These are very irregular in length. 

 The sheaths are close and finely toothed. 



The plant grows from two to three feet high, 

 in shallow water, and is sometimes called Swamp 

 Horsetail. 



The fertile spikes are small, oblong-ovoid ; 

 they mature in July. 



SEDG-E-LIKE HORSETAIL. 



Equisetiiiii scirpoides. 



The stems are numerous, all being simple, 

 slender, flexuous, thread-like and curving. They 



