Fig. 217.— Longitudinal section ol MacrocysHs ^yrifera, showing 

 sieve-tubes, /, and sieve-plates, s, with callus (x 300). (After 

 Oliver.) 



Pig. 216. — Chorda Jilum Stackh. a, uppermost and lowermost portion of frond (natural size); h. 

 transverse section, showing^ differentiation into cortical and epidermal layers ( x 200). (After Hauck.) 



R 2 



