104 



PRACTICAL COURSE IN BOTANY 



C sb , h P 



121 



R 



-A 



Figs. 120-121. — Transverse and longitudinal sections of a fibrovasoular bundle 

 in the stem of a sunflower. The two sections are lettered to correspond : M, pith 

 (parenchyma) ; X, xylcm region ; P, phloem ; R, cortex ; s, spiral ducts ; s', annular 

 ducts: t,t, pitted ducts; C, cambium between the phloem and xylem regions; sb, 

 sieve tubes; 6, bast; e, bundle sheath; ic, cambium (parenchyma) cells; h, wood fioers. 



