THE ROOTS OF WEEDS. 31 



other individuals of the same species. The generic and specific 

 names given to a plant or animal usually have some well defined 

 meaning, Rumex in the case mentioned meaning "a spear," from 

 the shape of the leaves of the little sour dock or field sorrel, while 

 crispu? refers to the curled or wavy margins of the leaves of the 

 curled dock which bears the name. 



PARTS OF A WEED. 



In order that the farmer or other person may be able to distin- 

 guish from the descriptions given any one of the 150 weeds listed 

 it will be necessary for him to know the names, structure and uses 

 of a few of the principal and more prominent parts of a weed. As 

 all of our weeds are constructed on the same general plan the parts 

 of one will serve to illustrate the others with only certain differences 

 in some particulars. Let us take, therefore, the corn cockle which 

 is a common weed in wheat fields and examine carefully its differ- 

 ent organs and the uses to which they are put. 



If an entire specimen of corn cockle be pulled up after it has 

 been in blossom for some time it will be seen to have five general 

 parts or divisions which are well known to all farmers. These are 

 roots, stem, leaves, flowers and fruit or ''seed pods," and they will 

 be considered in the order mentioned. 



THE ROOTS OF WEEDS. Roots of weeds vary greatly in form, 

 size, length of life, etc. They grow downward or spread out below 

 the surface thus avoiding the light. Their chief duties are to sup- 

 port the plant in position and to gather for it moisture and food 

 from the soil. As already noted, the roots of annual plants like the 

 cockle live for but a single year. They are for the most part fibrous 

 and spreading, and annual weeds can usually be easily pulled by 

 hand. The roots of both annuals and perennials are usually greatly 

 divided in order to secure a firm hold upon the earth and to have 

 as large an absorbing surface as possible in contact with the soil. 

 In most weeds all the nourishment, except carbonic acid gas, comes 

 from the soil and must be in liquid form before it can be taken up 

 by the little hairs which are found in numbers upon the smaller 

 divisions of the roots. The plant foods such as potash, phosphorus, 

 nitrates, silica, etc., before they can be absorbed by these root 

 hairs must therefore be dissolved in the moisture of the soil, just 

 as we dissolve crystals of sugar or salt in water. Some roots, as 

 those of clover and most plants of the pea family, produce small 



