SECT. II. TUBES. 35$ 



even in the young shoot ; though they are gene- 

 rally to he observed by breaking it gently asunder, 

 and then examining the surface of the fracture with 

 a microscope. In this case they appear in small 

 fragments projecting from the surface, and some- 

 what uncoiled ; but if the shoot is split longitu- 

 dinally, a portion of them will sometimes be found 

 extended longitudinally on the surface of the fissure 

 in an uncoiled state. 



In the stem and branches of herbaceous plants But easily 

 they are generally discoverable without much dif- thTs^nV" 

 ficulty, accompanying the longitudinal fibres and branches 

 forming part of the bundles.. I have found them of herba - 

 in the stem and branches of the Burdock even in plants ; 

 winter, when the fragments of the mature plant 

 had become quite indurated by means of their 

 exposure to the weather. 



They are also very easily detected in the foot- As also in 

 stalk both of the leaf and flower, accompanying, br 

 rather seeming almost entirely to compose, the bun- 

 dles of longitudinal fibres. This may be well exem- 

 plified in the leaf-stalk of the Artichoke when 

 young and fresh, in the fibres of which they are not 

 only remarkably large and distinct, but also re- 

 markably beautiful ; some of them exhibiting in their 

 natural position the appearance of spiral coats in- 

 vesting interior fibres rather than that of forming a 

 distinct tube, and seeming when uncoiled to be them- 

 selves formed of a sort of net-like membrane, con- 

 sisting of three principal and longitudinal fibres. 





