THE SCOUR1NG-RUSHES. 25 



may be added that cattle will not eat it if there is any- 

 thing else to be had. The juice of the plant was once 

 thought to be useful in nosebleed and as an application 

 to wounds. 



The scouring-rush is found throughout North America 

 growing along streams, on the borders of swamps, and in 

 other low grounds. It is able to exist, however, with 

 much less moisture, and is frequently abundant along dry 

 railway embankments and on gravelly banks. There is 

 some variation in plants from different localities, the one 

 here described being the form common to the North- 

 eastern States. Its closely appressed sheaths and many- 

 grooved stems are characters that usually serve to identify 

 it. It is the most abundant of our evergreen species, and 

 is also found in Europe and Asia, extending in a more or 

 less broad belt around the earth in the North Temperate 

 Zone. It appears to be absolutely unharmed by the cold. 

 The water in the central hollow often freezes solid without 

 hurt to the plant. In exposed situations the stems on the 

 southern side turn a dingy brown in winter, but become 

 green again on the approach of a milder season. 



In the Mississippi Valley, and farther west, there is a 

 form called Equisetum liiemale intermedium which has 

 transverse bands of silex on the stems, looser, somewhat 

 funnel-shaped green sheaths with a narrow black-and- 

 white margin and deciduous or persistent teeth. It has 

 often been collected for Equisetum Icevigatum, which it 

 resembles in many ways, especially in the funnel-shaped 

 sheaths, but the internal structure is that of true hiemale. 

 Equisetum l&vigatum is also said to have annual stems, 

 but there is still some doubt upon this subject. In some 

 States, notably Nebraska, Equisetum hiemale intermedium 

 i$ considered of some importance as a forage crop. No 



