56 THE HORSETAILS. 



As in all species of liquisctuin in which there is a 

 marked difference between fertile and sterile fronds, the 

 fertile are first to push up, appearing shortly after those 

 of the field horsetail and in their early stages scarcely to 

 be distinguished from them. There is, however, from 

 the beginning, a greenish tinge to the stems, presaging 

 their subsequent vegetative functions, while the sheaths, 

 rather longer for their width than in Equisetum arvcnsc, 

 are tipped with long teeth of bright reddish brown. At 

 first the sheaths are dilated upward, but they soon 

 change to urn-shape on account of the swelling buds 

 within. The fruiting cone is about an inch long and 

 one third as wide. It is of the same general colour as 

 the stem, and consists of the usual number of sporophylls 

 borne above the topmost sheath on a pedicel t\vo or 

 three inches long. 



Before the spores are ripe, whorls of branches have 

 begun to develop from the upper joints. Sometimes 

 even the lowest whorl of sporophylls push out a few 

 short branches. The fruiting parts usually wither as 

 soon as the spores are shed, while the rest of the stem 

 continues to develop branches and soon is hard to dis. 

 tinguish from the wholly sterile fronds, except that the 

 sheaths are somewhat larger and the apex of the stem 

 not so slender and tapering. 



The sterile fronds closely follow the fertile, and when 

 fully developed may reach a height of three feet. The 

 stem is slender and has twelve to eighteen grooves, the 

 ridges between being rough with small particles of silex ? 

 but never rough enough to be noticeable. The lower 

 nodes do not produce branches, but above there is a whorl 

 of branches at each node, the lowermost reaching a length 

 of three to six inches, and the others gradually decreas- 



