ELEVENTH AXXI'AL YEAR BOOK— PART XI 



755 



at the apex, and the sides of the lemma are devoid of the ridges which 

 are distinct in seeds of Kentucky bluegrass seeds. The extent of adul- 

 teration is determined from 1,000 seeds of the mixture counted indiscrim- 

 inately. 



Since it is difficult to remove all the sterile chaff from seeds contain- 

 ing a grain, it will suffice in making practical tests to remove the light- 

 est chaff, pieces of stems, leaves, etc. as inert matter, endeavoring to leave 

 all the grain-bearing seeds with the pure seed, which by this method 

 will contain also some empty, or sterile, seeds. The pure seed and chaff 

 are separated by placing the weighed sample, a little at a time, on a 

 smooth cardboard tray and pouring it into another tray, allowing the 

 seeds to roll across the face of the tray. The light chaff is held behind 

 while the heavier grain-bearing seeds roll off. Carefully repeating the 

 operation two or three times effects a very satisfactory separation. After 

 removing the foreign seeds, the seeds (200 in duplicate) for the germi- 

 nation test are to be counted out from the "pure seed" separation, the 

 chaffy and grain-bearing seeds being taken indiscriminately. 



Kentucky bluegrass seed should be comparatively free from chaff, but 

 the methods of cleaning in use leave from 10 to 20 per cent or more 

 of chaff with the pure seed. 

 Some samples show the purity 

 ranging from 80 to 85 per cent 

 but most tests range from 70 to 

 80 per cent and may fall much 

 lower. The viability ranges 

 from SO to 90 per cent in the 

 best samples, but most tests 

 range from 65 to 80 per cent and 

 many fall lower. The method of 

 making the purity test given here 

 tends to give higher purity and 

 lower viability man more care- 

 fully made official tests. The 

 most of the sprouts appear with- 

 in nine or ten days, others ap- 

 pearing from time to time until 

 the twenty-eighth day. Only a 

 very light covering, if any, 

 should be placed over the seeds. It is better that they remain uncovered 

 on the cloth or paper if the inverted dish keeps the air about the seeds 

 moist. 



The noxious weed seeds found in Kentucky bluegrass seed include: 

 Dock, small-fruited false flax, corn gromwell, rat-tail plantain, buck- 

 horn, also Canada thistle when mixed with Canada bluegrass. 



Other weed seeds found in Kentucky bluegrass seed include: Sedge, 

 sorrel, lamb's-quarters, mouse-ear chickweed, peppergrass, shepherd's 

 purse, cinquefoil, dog fennel, cat's-ear, hawkweed. 



Fig-. 29. — Seeds of redtop representing 

 the "fancy" (or "solid") grade of the 

 trade: a, Different views of seeds 

 having- the -white, papery, inner chaff; 

 b, two views of a grain, or kernel, 

 with the inner chaff removed; c, the 

 same, natural size. 



