180 , STATE BOARD OF AGRICULTURE. 



Blotting paper and filter paper may also be used in place of cloth with very- 

 satisfactory results. This is the usual method pui-sued by the writer in seed test- 

 ing, the paper used being a thin, gray absorbent paper much like that used by 

 druggists for filtering liquids. This paper is first folded in several thicknesses 

 marked and moistened, after which the seeds are sprinkled between a fold and 

 placed in the testing plate. 



EXAMINIXG THE WEED SEEDS. 



The weed seeds which have been separated from the sample of clover, alfalfa or 

 other seed under examination, should be carefully sorted under the lens, and 

 Identified if possible. This work requires careful attention to details, in order 

 to be satisfactory, and the person with little or no botanical training may not 

 expect to do much in the naming of the weed seeds which will be found. How- 

 ever, it will be possible for many persons to identify some of the more common 

 v/eed seeds which occur in clover and alfalfa and which would be a nuisance if 

 sown on a field not previously infested. 



In order to make this naming of weed seeds as easy as possible figures from 

 photographs are shown of a few of the most importance. These figures are en- 

 larged to about the same extent as if they were being seen through a low power 

 lens. Short descriptions of each kind of weed seed shown are also given and these 

 should be carefully studied in connection with the picture. 



This work of identification should be done by daylight if possible, the weed 

 seeds being placed on a sheet of smooth white paper on a table, near a window. 

 The lens, if without other support, should be held with one hand at the proper 

 distance from the seeds and the eye placed close down to the lens. Then with a 

 small bladed pocket or pen knife, or even a sliver of wood, the seeds may be sorted, 

 those of one kind being placed together. A record should be kept of the number 

 of seeds of each kind found in the sample and if a known part of a pound has been 

 used the total number of weed seeds in a bushel may be estimated. 



Most weed seeds can be distinguished from the seed with which they are mixed 

 by some difference in size, shape, markings on the surface, and color. In some 

 cases, however, the difference is so slight as to make it difficult for an inexperi- 

 enced person to tell them apart. This is especially true in the case of seeds of 

 dodder or "Love vine" which sometimes occur in western grown clover and alfalfa 

 seed. In fact seed known to come from the west or from Europe should always 

 be carefully examined for these weeds. Two" species of dodder are to be looked 

 for in clover and especially in alfalfa seed. These plants have the habit of grow- 

 ing as parasites upon the plants about them. They are very simple little vine-like 

 plants without leaves but consisting of slender, yellowish, wiry stems which twine 

 about the clover and alfalfa plants causing them to die down. Sometimes whole 

 fields of alfalfa are destroyed or severely weakened by the presence of these para- 

 sitic vines, hence the presence of their seeds in clover and alfalfa seed becomes a 

 serious menace to the growing of these forage plants. 



Fortunately the seeds of the more common of these two dodders, (Cuscuta 

 epithymum) are considerably smaller than those of alfalfa and red clover seed 

 hence can be successfully removed by screening with a sieve of twenty meshes per 

 linear inch. The seeds of the other dodder, however, (Cuscuta arvensis) are 

 sometim-es as large as the smaller seeds of clover and alfalfa, hence screening 

 cannot be entirely relied upon in this case without sacrificing much seed. It is 

 advisable, therefore, to reject any seed in which the seeds of this dodder are found. 



Where dodder has been seeded with clover or- alfalfa its presence will be indi- 

 cated by the appearance of more or less rounded, spreading areas in which the 

 plants are dying down, and if examined at close range the thread-like twining 

 stems of the dodder will be found covering them. These areas can be readily seen 

 even at some distance as they present a yellowish or light orange colored appear- 

 ance. When discovered the plants within this area and for a couple of feet beyond 

 should be cut, allowed to dry and burned, or straw may be spread on these spots 

 and burned to destroy the dodder and prevent its forming seeds. 



The Russian thistle is another pest which is being disseminated by means of 

 Western grown seed, and while the plant may not prove to be a serious weed on 

 loam and clay, it is gaining a foothold in the sandy portions of our state. 



