30 Elementary Work in Botany. 



than two feet high mallows or filaree,* for example will 

 best serve your purpose. Do not pull it up, but with a 

 spade or shovel, forced the full length of the blade into the 

 ground, pry or lift the plant out of the ground. Put it with 

 the adhering earth into a bucket of water. Holding it by 

 the base of the stem, move the roots up and down until 

 most of the earth is thus removed, then take the plant out 

 and finish washing the roots in fresh water. It may be left 

 in water over night and taken to school in a newspaper. 

 In washing, do not rub the roots with the hands. Look 



out for fine hairs on smaller rootlets. 



\ 



EXERCISE 19. 



Study of an Herbaceous Plant. Observe the roots. 

 Is there any definite order in the arrangement of root 

 branches or rootlets ? Look for hairs on the smallest 

 rootlets.f 



*The two Er odiums {E. cicutarium and E. moschatum} are known everywhere 

 as filaree. This name is a corruption of the Spanish Aljilaria, but is so well estab- 

 lished that to use the Spanish name is pedantic. 



f They take up water, which carries dissolved earthy substances to the leaves. 

 Carbon dioxide is absorbed from the air through the upper skin of the leaves. 

 A little of the water, together with the carbon dioxide, is made (digested) into 

 starch in the leaves. Some of the water carries the starch (really the starch is 

 first changed to glucose) to the growing parts of the plaint, where it is converted 

 into the various tissues, or it is stored for future use. Most of the water absorbed 

 by roots through the hairs goes out of the leaves through microscopic holes in 

 their lower surfaces. Water and carbon dioxide make more than nine-tenths of 

 all the food consumed by plants. Carbon dioxide is the gas which passes off in 

 bubbles from soda water. When a plant decays or burns it unites with oxygen, 

 forming carbon dioxide, water and a little ashes. 



