SUNFLOWER APICAL BUD 79 



but a narrow band of secondary fascicular tissue : the 

 identity of the original bundles can thus be recognized 

 at a glance. These points can be very well observed 

 in the stem of Eicinus and other herbaceous or semi- 

 herbaceous Dicotyledons. (Compare Fig. 4, A, B.) 



The young stem of Clematis Vitalba is also very good 

 material for the demonstration of the origin and position 

 of interfascicular cambium. 



In some stems (species of Ranunculus, &c.) the inter- 

 fascicular cambium is entirely absent. 



In woody perennials (e.g. Elm, Pine) the cambial 

 activity begins at a very early period, so that it is 

 difficult at times to recognize the original bundles from 

 the products of the interfascicular cambium, or inter- 

 mediate bundles : in these plants the activity of the 

 cambium is continued at intervals throughout life. See 

 below, p. 88, &c. 



Apical Bud. 



V. Take the apical bud of a young plant, or of a 

 young lateral branch of the Sunflower, and cut longi- 

 tudinal median sections : treat with potash, and mount 

 in glycerine : a better method is to treat with " eau 

 de javelle," and mount as directed on p. 50 : examine 

 with a low power, and then observe 



1. That the axis ends in a naked, broadly-conical 

 apex (punctum vegetationis), which is surrounded and 

 enveloped by 



2. Leaves : these may be observed in various stages 

 of development, the youngest being nearest to the apex : 





