THE STEM. 167 



greatly compressed, and the outside portion much 

 stretched in the original condition. When set free the 

 outer part contracts and the inner expands, and so 

 produces the coiling up. 



The ascent of water in the stem may be easily 

 shown by a few simple experiments. Any healthy 

 plant in full flower and foliage, such as a Fuchsia or 

 Marguerite will be found suitable. The stem should 

 be cut clean across at about 1-2 inches above the 

 ground. To the stump a glass tube may be connected 

 by a piece of indiarubber tubing ; another glass tube 

 should also be connected with the base of the stem in 

 a similar way. The first tube will show the manner in 

 which the root pours water into the stem ; the water 

 accumulates in the glass and may eventually rise to 

 three or four feet. One of the best plants to show this 

 experiment is Sparmannia. A Vine stump 2| cm. 

 thick has yielded five kilogrammes of water in a 

 week. 



The second tube attached to the stem of the plant 

 will suck up water and show the daily supply which 

 is necessary for the stem and foliage. This can 

 easily be measured, and gives a vivid idea of the 

 loss of water, or transpiration. The same method 

 may be used to show that life is going on in 

 branches during the winter. A leafless Sycamore twig 

 wlW not only absorb a large amount of water, but will 

 even cure deep wounds by forming resin over the scar 

 where a twig has been broken away. The water in the 

 vessels and tracheids of stems in their natural state, is 

 said to rise at a rate of from 36 to 154 cm. per hour. 

 The speed varies with the season, and with the hour of 

 the day. Very little water seems to be used at night ; 

 the greatest amount is taken up generally about the 



