vii] RHIZOIDS OF THE HORNWORT 89 



Guppy found that the shoots were mostly killed by five or six 

 days inclusion in ice. 



Fig. 58. Ceratophyllum demersum, L. 

 A, single leaf of a rhizoid. B, single 

 leaf of a water shoot (Enlarged.) 

 [After Gliick, H. (igo6), Wasser-und 

 Sumpfgewdchse, Bd. ii. Figs. 27 A 

 and B, p. 195.] 



Fig. 57. Ceratophyllum demersum, L. 

 Part of an axis, A , which is lying on 

 the soil and bears a normal leaf- 

 whorl, B, and a rhizoid penetrating 

 the soil. The lowest leaf-whorl of 

 the rhizoid, U, has transition leaves. 

 (Slightly enlarged.) [After Gluck, H. 

 (1906), Wasser-und Sumpfgewdchse, 

 Bd. II, PI. VI, Fig. 76.] 



The various peculiarities of structure and habit to which 

 we have referred in the preceding pages, are not the only 



