28 PRODUCTIVE FARMING 



Examining for Impurities. Weed seeds and other im- 

 purities can usually be seen with a common reading glass or 

 pocket microscope. The proper thing to do is to examine 

 seeds before buying them, and avoid spending money for 

 weed seeds to sow on the farm. At least let us look at the 

 seed before sowing it (Fig. 14). 



Weeds have been briefly defined as "plants out of place. r> 

 This is a satisfactory meaning of the term, for many plants 

 that are grown for the uses of man are objectionable when 



FIG. 13a. Hay-field filled in late summer with wild carrots or Queen 

 Anne's lace. 



FIG. 13b. Hay-iield "taken" by dandelions. 



found among other crops. Rose bushes sprouting in a corn- 

 field are called weeds. Likewise corn in a rose garden is 

 considered as a weed. Noxious weeds, however, are those 

 plants which are very frequently found in fields, or gardens, 

 or other undesirable places. 



Classification. Weeds may be grouped, according to 

 the length of life, into annuals, biennials, and perennials. 



Annual weeds bear blossoms and seeds the first year 

 and then die entirely. This group includes many of our 

 most abundant weeds, such as rough pigweed, lamb's-quar- 



