XXV] 



ANKYROPTEEIS 



457 



another leaf-stalk. A root of another plant has invaded the 

 cortex at R, fig. 314, C. 



The form and structure of the stele is diagrammatically 

 represented in fig. 314, B. The outer portion (black) consists 



B 



Fio. 314. Anhyropteris corrugata. R, intruded root; P, petiole; S, stele, Sw 

 sieve-tubes. 

 A, B. From a section in the University College Collection. 



C. After Williamson. 



D. From a section in the Williamson Collection (British Museum). 



of a cylinder of scalariform tracheae in which the position o 

 groups of smaller elements (protoxylem) is shown by the whit e 

 patches. The xylem is thus seen to be mesarch. The pro mi. 

 nent group of xylem on the lower right-hand side of the section 



