n6 HOW TO KNOW THE FERNS 



marked with lines, and at intervals are en- 

 closed in sheaths ; these have long teeth and 

 fit the stem very closely. The branches are 

 rough to the touch, and have sheaths which end 

 in four or five teeth ; each tooth in this case is 

 prolonged into a bristle which has two toothed 

 ribs. This is a feature by means of which it is 

 always possible to distinguish the Great Horse- 

 tail from any other species. Now and again 

 stems have been found which, whilst bearing 

 fertile cones, at the same time branch in the 

 manner to be observed in the case of the barren 

 stems. 



The Great Horsetail is widely distributed and 

 is sometimes very abundant, though it is not so 

 common as some of the other species of Equise- 

 tum. 



Equisetum pratense. In this case the specific 

 name is a Latin word which means " growing in 

 a meadow." In some books this plant is known 

 as E. umbrosum. The Shade or Blunt-topped 

 Horsetail. 



This species has three kinds of stems. The 

 first of these is about six inches in height, and is 

 provided with large loose sheaths. This bears 

 the cone of fructification, which is ripened about 

 the month of April. The second type of stem 

 produces both branches and a fertile cone, 

 though this latter is very much smaller than in 

 the case of the first type of stem. Finally, 

 there is the barren stem, which may be about 

 eighteen inches in height ; this is very rough, 

 and has about twenty strongly-marked ridges. 

 The sheaths, which are not so large as those of 

 the fertile stem, fit somewhat closely. The 

 stem branches freely, and it is to be noted that 

 these branches have three or four ridges ; as 

 well, they bear sheaths which end in the same 



