SEEDS WEEDS. 551 



of seeds required in the sample should be increased from 300 to 400. 

 Where the germinative ability is less than 75 per cent at least GOO 

 seeds should be tested. As the germinative power approaches 75 per 

 cent the number of seeds tested should be from 800 to 1,000. Where 

 there is no indication as to the relative value of seeds, a sample of at 

 least 400 seeds should be tested, and after the preliminary test is made 

 an increased number, as indicated above. 



The Russian thistle, J. Wilson, L. H. Pammel, G. E. Patrick, 

 and J. L. BuDD (Iowa Sta. BuL 26, pp. 33, pis. 9). — The last general 

 assembly of the State of Iowa passed a liussian-thistle law, providing 

 that a bulletin should be prepared by the State Agricultural College 

 on the Russian thistle and means for effecting its extermination. 

 Upon the passage of this act steps were taken to follow its require- 

 ments. Seed was procured and grown on the college grounds, in rod- 

 square plats, alone, with timothy and with red clover, on various soils. 

 On plat 1 the seed was planted 3 in. apart in rows. But few plants 

 grew, and these made the largest plants grown on any of the plats. 

 On plat No. 2 the seed was planted the same as on the previous one. 

 Red clover was raked in over this plat, but the season was so dry that 

 it did not grow. The thistle came up thinly and grew vigorously. 

 Plat No. 3 was drier land than the others. It was planted as the 

 other two and timothy seed raked in. The thistles made a thin stand 

 and grew well, but the timothy seed, owing to the drought, did not 

 make any growth. The fourth plat was sown thickly with seed, which 

 came up thickly, and nuide a growth of from 12 to 20 in. high. 



When the thisHe first comes up it is soft and velvety to the touch. 

 Sheep and cattle eat it in its young stage, but horses and hogs refuse 

 to touch it. The plants are of very rapid growth, and become prickly 

 so soon that it gives a very short grazing period, not longer than 6 

 weeks or at most 2 months. 



With regard to the remedies, it is easily killed. When cut off at the 

 surface of the ground before seeding it dies. When the plants are not 

 more than 6 in. in height, careful plowing with a drag chain and har- 

 rowing to fill up crevices between the furrows will kill every plant 

 that can not get its leaves to the surface. Waste places and the edges 

 of fields must be looked after carefully, as these seem to be favored 

 localities for its growth. Attention must be given to the weeds before 

 they assume the tumbleweed shape, as they then can scatter their 

 seeds very widely. 



The botany of the Russian thistle (pp. 8-25). — Various authors are 

 quoted as to the origin and distribution in the United States of the 

 Eussian thistle {Salsola l-ali tragus). Other plants are frequently mis- 

 taken for the Russian thistle, and on this account the author has given 

 illustrations and descriptions of the spiny nightshade {Solanum rostra- 

 turn), horse nettle (;S^. carolinense), prickly lettuce {Lactuca scariola), 

 and lance-leaved thistle {Cnicus laneeolatus), and descriptions of Ama- 



