THE FIBBO- VASCULAR SYSTEM. 



117 



146. — The bundle of the adTentitions root of Ranunculus 

 repens is very diiierent from the one just described. It may 

 be briefly described as composed of a mass of tracheary tis- 



Fig. 106.— Transverse section of hypocotyledonary portion of stem of Sicinus com- 

 munis, r, r, parenchyma of the primary cortex ; m, parenchyma of the pith -, 6^ 

 ijast fibres ; y, y. soft, bast ; c, cambium ; g, g, large pitted vessels ; t, t, smaller pit- 

 ted vessels ; cJ, continuation of the cambium into the parenchyma lying between the 

 imndles — the parenchyma-cells are repeatedly divided by tangential walls. Between 

 the primary cortex r and the ftbrons tissue of the phloem lies a layer, the so-called 

 bundle-sheath, filled with compound starch grains. Highly magnified.— After Sachs. 



sue, which is cross-shaped, as seen in transverse section {g, 

 r, g, Eig. 108), and four masses of sieve tissue, which lie in 

 the angles between the projecting portions of the tracheary 

 tissue. Around the whole is a layer of pericambium (^j, 



