282 



MORPHOLOG v. 



plant begin to appear above the ground. One of these is shown 

 in fig. 325. This lias a much more slender stem and is pro- 



Fig. 323. 



Spore of equisetum 

 with elaters coiled up. 



Fig. 3=4- 

 Spore of equisetum witlr elaters un- 

 coiled. 



vided with numerous branches. If we ex- 

 amine the stem of this shoot, and of the 

 branches, we see that the same kind of 

 leaves are present and that the markings on 

 the stem are similar. Since the lea\'es of 

 the horsetail are membranous and not green, 

 the stem is green in color, and this per- 

 forms the functitm of photosjaitliesis. These 

 green shoots live for a great pan of 

 the season, building up material which is 

 carried down into the underground stems, 

 where it goes to supply the forming fertile 

 shoots in the fall. On digging up some of 

 these plants we see that the underground 

 stems are often of great e.vtent, and that 

 both fertile and sterile shoots are attached 

 to one and the same. 



576. The scouring rush, or shave grass. 

 — Another conunon species of horsetail in 

 the Northern Slates grows on wet lianks, 

 or in .sandy soil which contains moisture 

 along railroad embankments. It is 

 the scouring rush (E. hyemale), so ^-^fi 

 t:alled because it was once used for / 

 polishing purposes. 'I'his plant like F' 



all the species of the horsetails has setu," arvensis' 



ni horsetail (Equi. 



