xvi] 



ROOT ANATOMY 



209 



'iG. 138. Callitriche 

 tagnalis, Scop. T.S. 

 entral cylinder of ad- 

 entitious root of water 

 Drm (X470); s, sieve 

 ube. [Schenck, H. 

 (1886).] 



Fig. 139. Vallisneria spiralis, L. A, T.S. adventitious root 



(x 240). 5, T.S. central cylinder (x 470); end, endodermis, 



s, sieve tubes of which three are present. The central vessel 



is unthickened. [Schenck, H. (1886).] 



Fig. 140. 

 major. All. 



T.S. central region of roots of Naias, sieve tubes shaded. A, Naias 

 , two central vessels. B and C, N. minor, All., one central vessel in B 

 and two in C. [Sauvageau, C. (1889I).] 



A. w. p. 



14 



