MORPHOLOGY 



1-29 



called the INTERFASCJCULAK CAMBIUM, develops in the primary 

 medullary rays between the original bundles, and, uniting with the 

 cambium in the bundles, forms a complete cambium ring. This 

 cambium ring is thus composed of two distinct forms of meristematic 

 tissue : for while the cambium of the bundles or the FASCICULAR 



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rrp 



FIG. 138. Transverse section of a stem of Aristolochia Siplw in tin; Hist year of its growth, showing 

 a vascular bundle with cambium in active division, p (Vascular .parenchyma i'lp proto- 

 xylein ; TO' and TO", vessels with bordered pits; ic, interfascicular cambium in continuation 

 with the fascicular cambium ; v, sieve-tubes ; cftp, protophloem pc, pericycle ; sk, inner part 

 of ring of sclerenchymatous fibres, (x 130.) 



CAMBIUM consists of primary meristem (p. 99), the connecting zone 

 of interfascicular cambium is of later development, and js consequently 

 a secondary meristem (p. 99). A cross-section of a young stem of 

 Aristolochia Sipho, with the cambium ring in process of formation, is 

 represented in Fig. 137; in Fig. 138 a single bundle of the same 

 cross-section, more highly magnified, shows the fascicular cambium 

 with the interfascicular cambium to either side in a condition of 



