11 



HORSETAIL FAMILY {Equisetacece) 



COMMON OR FIELD HORSETAIL (Equisetum arvense L.) 

 Plate III (To face page 12). 



Common Names: Among the popular names of horsetail are the 

 following, which are typical and descriptive: pine-top, meadow-pine, 

 scouring rush, bottle brush, snake-pipes, jointed rush, and cornfield horse- 

 tail. 



Description: The horsetails or scouring rushes are a group of 

 perennial plants intermediate between the ferns and club-mosses. Like 

 the ferns they possess a moi;iii^less branching, creeping rootstock which 

 persists from year to year and sends out new shoots each year. The 

 rootstock of the field horsetail develops also short tuber-like branches, 

 which act as storehouses of reserve material. As in some of the ferns, the 

 rootstock sends up two distinct kinds of leaf-shoots, a fertile and a sterile 

 shoot, each of which is distinctly jointed and hollow. The fertile stems, 

 which bear the spores, or reproductive bodies, appear early in May, before 

 the sterile or vegetative shoots have yet unfolded. They are from four 

 to ten inches high, usually unbranched, light-brown, with darker brown, 

 scale-like leaves arranged in circles at each joint or node. At the apex 

 of each fertile stem is a group of sporophylls known as the cone, from which 

 the spores fall to the ground and produce new plants. The spores are 

 round, and each is furnished with two spiral bands or elaters (so attached 

 as to appear to be four) which assist in its dispersal. The sterile stems 

 are from four to twenty inches high, bright green, grooved, with angled, 

 solid branches. 



Distribution: The field horsetail is native to Canada, and is found 

 in gravelly or sandy soil from Newfoundland to Alaska. 



Poisonous Properties: The harmfulness of field horsetail has for 

 many years been the subject of much discussion and difference of opinion, 

 but in Canada it was found to be the cause of much loss (see Dominion 

 Expierimental Farms Reports 1910, p. 200, 1912, p. 210-11.) The toxic 

 principle has not been determined. 



Animals Affected: Horses suffer most from eating this weed in the 

 hay, particularly young horses. It is also known to be injurious to sheep, 

 but there is a difference of opinion as to its effect upon cattle. The weed 

 does not appear to be as poisonous when eaten in a green state. This may 

 be due to the laxative properties of other fresh food eaten at the same 

 time, or to the fact that the plant is not as common in pastures as in 

 meadows and, in consequence, is not eaten to the same extent. Animals 

 grazing in pastures containing horsetail, should be watched and removed 

 from the field of danger at the first symptoms of poisoning. 



