WESTERN SNEEZEWEED AS A POISONOUS PLANT. 41 



The scythe cutting was repeated in the summers of 1919 and 1920, 

 with no change in results. 



It seems clear that scythe cutting has no deleterious effect on the 

 growth of the plant. 



Effect Produced on the Plant by Restriction of Grazing. 



Inasmuch as it is recognized that the present abundance of H. 

 hoopesii on some ranges is correlated with the overgrazed condition, it 

 is desirable to determine what effect would be produced by removing 

 grazing animals for a period. The II. hoopesii is not particularly 

 palatable to any grazing animals. Cattle very rarely eat it even when 

 the range is reduced to an almost pure stand of this plant. The sheep 

 eat it only after most of the desirable forage has been removed. 

 Under such circumstances the H. hoopesii, which is a rank-growing 

 plant, takes almost complete possession of the range. If the grazing 

 animals were removed and the range allowed to reseed itself, it might 

 be possible that by the growth of grasses and weeds the H. 

 hoopesii would be gradually diminished in abundance. In order to 

 test this possibility, a locality was selected on an evidently overgrazed 

 range where the H. hoopesii was very abundant, and about one-fourth 

 of an acre was fenced off, the plan being to keep it under obser- 

 vation for a term of years. This area was on a very heavily grazed 

 cattle range on which little remained except the H. hoopesii, and that 

 was very abundant. 



The land was fenced off on September 16 and 17, 1915, and on 

 September 24 half of the plot was sowed to grass seed. Timothy was 

 seeded on a part of this and orchard grass on the rest. The grass seed 

 was scattered broadcast and was not raked in. 



The area was visited on June 23, 1916. It was found that the 

 fence had been broken down during the winter and the ground more 

 or less trampled. There was no evidence that any of the grass seed 

 which had been sowed had germinated ; in fact there was more grass 

 on the part of the plot which had not been sown than on the remainder. 

 The general appearance of the tract was very much better than that 

 of the ground outside of the fence: Evidently considerable grass 

 had grown in the inclosure. 



On August 12, 1916, it was noted that an abundance of wild 

 grasses was coming in so that the H. hoopesii at this time was more 

 or less obscured. Outside the area very little grass was seen. 



September 6, 1917, practically two years after the plot was fenced 

 off, another examination was made. To superficial observation the 

 II. hoopesii seemed nearly as abundant within the inclosure as 

 outside, but there was a good growth of wheat grass with a good 

 deal of yarrow and many dandelions. Actual count of the number 

 of H. hoopesii plants on measured typical areas inside and outside 



