CUCURBITA 



599 



two or more larger, later-maturing, pitted vessels which lie on 

 the outer face of the tangential band. (Fig. 314, A.') The inner 



■~i ca 



Fig. 311. A-F, transections of sectors of root and hypocotyl showing stages in vascular 

 transition: A, upper level of primary root; B, lower hypocotyl showing pith; C, 4 mm. 

 above B; D, hypocotyl about i mm. above C in which inner cambium is forming; E, about 

 1.5 above D in which metaxylem groups are bifurcated and there is a definite inner cambium 

 and inner phloem ; F, one of transition bundles showing lateral position of protoxylem, 

 inner cambium, inner phloem, interfascicular phloem and some of connective phloem cells : 

 ca, cambium; en, endodermis ; i ca, inner cambium; i ph, inner phloem; mx, metaxylem; 

 pel, pericycle ; ph, phloem ; pi, pith ; px, protoxylem. (After Rutledge.) 



