'I'liK Brij/KTiN. 55 



EXPLANATION OF PLATES. 



The figures of the following plates are illustrations of agi'icullural 

 seeds and weed seeds which occur as impurities. It is hoped that by 

 consulting the illustrations the farmers may be aided in determining the 

 j)urity of seeds. A magnifier such as shown in Fig. 1 is most helpful 

 in examining seeds. 



In referring to the illustrations, the term "seed" is used in its popular 

 sense, since in many instances what is called the seed is more properly 

 a seed-like fruit containing a true seed. Examples of this are the grasses, 

 buttercup, field-madder, ragweed, and dandelion. 



Grass seeds have a kernel, or grain, which is usually covered by one 

 or two more or less persistent pairs of chaffy scales. In some cases 

 these scales fall away, leaving the grain free, as in case of wheat and 

 rye. These pairs of scales are referred to as the ''outer hull" and "inner 

 hull." If both are present, this is indicated by "hull double." Illus- 

 trations of seeds with single hull are oats, Kentucky blue-grass, and 

 orchard grass, while sweet vernal-grass and crab-grass are seeds with 

 double hulls. Examination of the figures of grass seeds on plates I and 

 II will further make this designation clear. 



The purpose of the brief descriptions is to supplement the illustrations 

 by the noticeable characters and to state the commonest occurrences of 

 the seeds as impurities. The shape, markings, and natural size of the 

 seeds appear in the illustrations. 



The figures in the plates are given in the sequence and, as far as 

 possible, named according to Britton's Manual, third edition. The scien- 

 tific names are given for accurate identification, as in many sections the 

 common names differ. 



