106 



Plant Physiology 



and the like permit of diffusion, and in the end the 

 demands of each cell govern the flow toward that cell. 



63. Fibrovascular bundles. If freshly cut (under 

 water) shoots of the jewel-weed, sunflower, Indian corn, 

 canna, .or other convenient rep- 

 resentatives of monocotylous and 

 dicotylous plants are placed in 

 a solution of a dye such as eosin 

 or fuchsin, the stain will pass 

 upward through the conducting 

 system of the plant, and the 

 paths of conduction may thus be 

 made evident, although there is 

 sometimes a slight lateral diffu- 

 sion tending to obscure the defi- 

 nite channels. 



It will be recalled that mono- 

 cotylous plants are characterized 

 by stems in which the vascular 

 strands are commonly distributed 

 in irregular manner throughout a 

 ground tissue called 

 parenchyma, as in corn 

 or sorghum. A hand 

 section will show at a 

 glance this distribution 

 of the bundles, and it 



FIG. 34. Vascular system of Clematis, 1S als Strikingly 

 apical portion of the stem : longitudinal brought Out by break- 

 view of stem and leaf trace bundles (A), j nff j_ v corn gtalk 

 and cross-section of internode (B). 

 [After De Bary and Nageli.] through an internode 



