XII 



EQUISETINEJE 



469 



shoot. Very early the cells of the leaf-base immediately above 

 the young bud grow around it like a sheath, and finally become 

 grown together with the epidermal cells of the axis above tlie 

 bud, which thus lies in a completely closed cavity. As the bud 

 grows it gradually destroys the tissue surrounding the cavity, 

 and finally breaks through the base of the leaf, appearing from 

 the outside as if it had developed from below and not from the 

 axil of the leaf. In most species these branches remain simple, 



Fig. 273. — Section of a lateral bud, enclosed within the sheath formed by the leaf-base, 



X175. 



but in E. sylvaticum and E. giganteum the secondary branches 

 also ramify. 



The Roots 



The formation of the roots is intimately connected with that 

 of the lateral buds. Each bud normally produces a single root 

 below the first foliar sheath, which in the buds derived from the 

 rhizome all develop, whether the buds themselves grow further 



