PATH OF MOVEMENT. 



49 



leaves of some of the plants used. After the shoots have been 

 standing in the solution for a few hours, if we cut them at 

 various places we will note that there are several points in the 

 section where the tissues are colored red. In the impatiens 

 perhaps from four to five, in the sunflower a larger number. In 

 these plants the colored areas on a cross section of the stem are 

 situated in a concentric ring which separates more or less com- 

 pletely an outer ring of the stem from the central portion. If 

 we now split portions of the stem lengthwise we see that these 

 colored areas continue throughout the length of the stem, in some 

 cases even up to the leaves and into them. 



96. If we cut across the stem of a corn plant which has been 

 in the solution, we see that instead of the colored areas being in 

 a concentric ling they are irregularly scattered, and on splitting 



Fig 57. 

 Broken corn stalk, showing libro-vascular bundles. 



the stem we see here also that these colored areas extend for long 

 distances through the stem. If we take a corn stem which is 

 mature, or an old and dead one, cut around through the outer 

 hard tissues, and then break the stem at this point, from the 

 softer tissue" long strings of tissue will pull out as shown in fig. 

 57. These strings of denser tissue correspond to the areas 

 which are colored by the dye. They are in the form of minute 

 bundles, and are called vascular bundles. 



