158 PLANT-LIFE 



avoiding the ploughshare or the spade. Giant Horse- 

 tails existed in remote geological times, when many 

 species flourished; but the family's day of glory has 

 departed, and the ancient aristocracy is now represented 

 by between twenty and thirty species, all included in 

 the solitary genus Equisetum. The greatest existing 

 member of the family, E. giganteum, grows in tropical 

 America ; it attains a height of about 30 feet, but it has 

 a very slender stem, and has to depend upon the support 

 of neighbouring vegetation. The smallest known species 

 is E. scirfoides ; its stems are about 6 inches long and 

 ^ig inch in diameter. Eleven species have been recorded 

 in Britain, and of these E. maximum {Telmateia, Ehrh.) 

 is the most impressive; its vegetative shoots rise to a 

 height of over 6 feet, and their graceful branchings and 

 delicate colouring render them very attractive. The 

 spore-bearing shoots appear solitary in the spring ; they 

 are not more than 10 inches high, and by the time the 

 vegetative shoots appear they have done their duty and 

 withered away. This species occurs in marshy, wet, 

 and shady places in temperate Europe, in Russian Asia, 

 and North America. 



All the species display a family likeness. The stems 

 are hollow, jointed, furrowed, and erect; the leaves are 

 much reduced; they form sheaths at the joints of the 

 stems; branches, when present, occur in whorls at the 

 leaf-sheaths. E. arvense, the Common or Field Horse- 

 tail (Plate VIL), an almost cosmopolitan species, maybe 

 taken as a type. The rhizome (Fig. 1, m) penetrates 

 2 or 3 feet beneath the surface of the soil; it possesses 

 leaf-sheaths, and sends out adventitious roots from its 

 nodes ; it also produces tubers from which new plants are 



