142 



PRACTICAL ADVICE ON SEED-TESTING 



third to one-half the price of those with which they 

 are mixed. Red clover, alfalfa, Kentucky blue- 

 grass and orchard-grass seed are the principal ones 

 affected. The seed of yellow trefoil is imported in 



Fig. 211. "Seeds" or perigynia of species of carex, sedge 

 plants that are sometimes found in grass seed. 



large quantities from Germany to be used as an 

 adulterant of red clover and alfalfa. It is a low- 

 growing, leguminous plant not cultivated in the 

 United States and of no value where red clover or 

 alfalfa will grow. Bur-clover seed, which is combed 

 out of South American wool, is also imported from 

 Germany and mixed with alfalfa seed. English 

 and Italian rye-grass and meadow fescue seed are 

 frequently mixed with orchard-grass seed in vary- 

 ing proportions. Canada blue-grass seed, although 

 used to some extent in this country, is imported in 

 large quantities from Ca;nada, to be mixed with, or 

 sold as Kentucky blue-grass seed. All of these 

 seeds used as adulterants resemble so closely the 

 seeds with which they are mixed that they' are 

 difficult to distinguish. In the following discussion, 

 enlarged pictures are given of the true seed, in 

 order that the examiner may distinguish adulter- 



Kg. 212. Red clover. 



Fig. 213. Alsike clover. 



ants. The sedges frequently occur with grasses but 

 are not used as adulterants. Some of the seeds or 

 fruits are shown in Pig. 211. 



Farm seeds and adulterants. 



B,KT) CLOVER (Trifoliumpratense). Fig. 212. Fresh, 

 well-matured seed is plump and has a slight luster. 

 The color is clear yellow, violet or variegated. Old 

 seed loses these colors, which are replaced by dull 

 brown. Artificial polishing produces a high luster 

 but does not redeem the original colors. Shriveled 

 screenings are thin owing to the poorly developed 

 embryo, and dull greenish or brown. Well-devel- 

 oped seeds are somewhat triangular, rounded and 

 have a broad notch at the scar. Samples of com- 

 mercial seed exhibit considerable difference in the 

 average size of the seeds. 



Alsike clover (Trifolium hyhridum). Fig. 213. 

 Seeds smaller than in red clover, averaging some- 

 what larger than white clover seed. Fresh seed 

 has little if any luster, but the olive to dark green 

 color is bright, and the mottled surface exhibited 

 by many of the seeds is distinct. Old seed loses its 

 green color and becomes dull brown, the mottling 

 becoming indistinct or disappearing. Such seed is 

 not readily distinguishable from old white clover 

 seed. 



Crimson clover (Trifolium incarnatum). Fig. 

 214. Crimson clover seed is readily distinguished 

 from that of the other clovers by the large size, 

 oval and more rounded form of the individual seeds. 

 Fresh seed is reddish pink and has a pronounced 

 luster. A dull reddish brown replaces these in old 

 seed. There is considerable variation in the size of 

 seeds in commercial samples. 



Alfalfa or lucerne (Medicago sativa). Fig. 215. 

 Fresh, well-matured seed has a clear greenish yel- 



Fig. 214. Crimson clover. 



Fig. 215. Alfalfa seed. 



low color but no distinct luster. Its greenish color 

 readily distinguishes it from the seed of the culti- 

 vated true clovers. Individual seeds vary consider- 

 ably in form, since several are produced in each 

 spiral pod. They are angular, oval -oblong or kidney- 

 shaped and usually have a light stripe on each side. 

 Yellow trefoil (Medicago lupulina). Fig. 216. 

 This seed is largely used as an adulterant of red 

 clover and alfalfa, and to some extent in alsike and 

 crimson clovers. Individual seeds are practically 

 the same size as those of red clover and alfalfa, but 

 larger than alsike seed and smaller than average 

 crimson clover seeds. The admixture of 35 to 45 

 per cent of this seed in red clover seed gives the 

 latter in bulk a greenish tinge. It lightens the 

 general color of alsike seed, but does not materially 

 change that of alfalfa or crimson clover seed. Its 

 detection is readily accomplished by examining in- 

 dividual seeds with a lens. The seeds are produced 

 singly in the pod and so are fairly constant in form. 



Fig. 216. Yellow trefoil, 

 aa adulterant. 



Fig. 217. Bur-clover, 

 as adulterant. 



