36 ELEMENTS OF PLANT ANATOMY. 
organized. These have been referred to in the table as sub- 
stances of less definite structure. 
8. Amides. 
These are soluble compounds, capable of crystallization, and 
are found in greater or less quantities in all young growing 
parts of plants. As already stated they arise from the dis- 
sociation of proteids and protoplasm, in order to make their 
transfer possible, and it is claimed that they are also formed by 
synthetical processes. The most widely distributed amide is 
asparagin, which is found not only in the young shoots of as- 
paragus but in nearly all plants. Leucin, tyrosin, glutamin, 
and others occur less frequently. 
9. Sugars. 
These are widely distributed in the different plant tissues, 
and are divided into two groups, cane and grape sugars. ‘The 
latter have the formula C,H,,OQ, and are fermentable. The 
principal sugars of this group are dextrose or glucose, and 
laevulose or fruit sugar. Glucose is the most common form, 
and is the one in which the most of the non-nitrogenous elements 
of food and building material are transported from place to place 
in the plant. 
The formula of the cane-sugars is C,H,,0,,, and they are for 
the most part unfermentable. One of this group, known as 
@ 
saccharose, occurs as reserve material in such plants as beets, 
sugar-canes, and maples. This, in order to be transported from 
the cells where it has been stored, must be changed to grape- 
sugar. Another important kind is maltose, the sugar formed by 
the germination of barley seeds. 
All, or nearly all, of the non-nitrogenous food products con- 
tain the three elements, carbon, oxygen, and hydrogen, and in 
works on plant physiology they are generally divided into two 
