THE HORSETAILS. 10$ 



Ferns, is followed with slight variation in Horsetails ; but there 

 is this difference a prothallus will develop either archegones or 

 autherids, rarely both. It may thus be said that there are male 

 prothallia and female prothallia, which may be separated by 

 their size and colour, apart from an examination of the organs. 

 The female is about half an inch in length and of a full green 

 tint ; the male is much smaller and of a yellow-green colour. 

 It is thought that the formation of archegones is fostered by a 

 full supply of nutriment, and that a scarcity of it results in the 

 production of antherids. 



Eight species of Horsetails are included in the British flora, 

 and, of course, several of the varieties have been by some 

 authors regarded as species. The genus is restricted in its 

 distribution mainly to the North Temperate regions, only a few 

 being sub-tropical. They rarely exceed two or three feet in 

 height, though Equisetum giganteum, a native of Tropical 

 America, is between twenty and forty feet high, and our own 

 E. maximum attains a height of five or six feet. They are 

 mostly found in damp situations where the soil is loose, and 

 some are marsh or aquatic plants. The extensively creeping 

 rootstocks, or rhizomes, are always perennial ; the stems mostly 

 annual, formed in miniature, underground, the year before, and 

 rapidly lengthening in spring. Tubers filled with starch, etc., 

 are often formed on the underground portions, and these retain 

 their vitality though adverse conditions may cause them to 

 remain dormant for years. 



The name is a compound formed from the Latin words equus, 

 a horse, and seta, a bristle, suggested by the texture of the 

 branches ; whilst the English name is obviously suggested by 

 forms such as the barren stem of the Field Horsetail. 



