334 EXPERIMENT STATION EECOKD. 



aud the cut ends placed in water. The next day those taken from the potassium 

 and sodium nitrate solutions had recovered except that some leaf tips were 

 dead. Greater injury was observed in those taken from the iron sulphate, 

 which showed black spots, while many of those from the sodium arsenite were 

 still wilted or were turning yellow. 



A small alfalfa plat sprayed in March, 1909, with 2 lbs. of iron sulphate per 

 gallon of water and another with a nitrate of soda-kainit mixture showed 

 somewhat lower yields than the unsprayed plats, but practically no weeds 

 except couch grass were present on any of the plats. 



July 3, 1907, 6 oz. each of the following substances were applied around the 

 roots of peach trees diseased with yellows in the effort to find something that 

 could be used to kill quickly trees: Chromic acid (i oz. in water), kerosene, 

 copper sulphate (1 oz. in water), carbon bisulphid, caustic soda (2 oz. in water), 

 salt (saturated solution in water), sodium hyposulphite (2 oz. in water), potas- 

 sium cyanid (1 oz. in water), commercial sulphuric acid, 2 per cent corrosive 

 sublimate, sodium nitrate (li oz. in water), iron sulphate (1* oz. in water), 

 gas tar, sulphurous acid. The earth 2 in. deep was raked away from the tree 

 and replaced after the chemicals had been poured in. Five days later, leaves 

 on the copper sulphate and carbon bisulphid treated trees showed marked 

 injury, but no others showed any effect. The copper sulphate-treated trees 

 recovered but those treated with carbon bisulphid died in a short time. In 

 the winter of 1909-10, sodium arsenite 4 to 8 oz. per gallon, salt 2 lbs. per 

 gallon, 1 to 2 gal. to a linear rod, and kerosene i to 1 gal. per rod, poured around 

 the roots of Japanese quince hedge failed to kill because of sprouting from the 

 roots some distance from the base of the stems. 



In September, 1909, kerosene, sodium arsenite (i oz. per qt.), carbon bisul- 

 phid, and chromic acid (i oz. per qt), were applied at the base of young i to 1 

 in. apple, peach, black locust and sumac trees, about 2 oz. per tree being given. 

 When examined a few weeks later, it was found that the kerosene caused but 

 little injury to the peach and apple, even when the bark was broken at the 

 base. The sodium arsenite and the carbon bisulphid had killed most of the 

 leaves and probably the whole tree in both peach and apple. No injury from 

 the chromic acid was noted. Another trial with 1 to 2 in. apple trees, in which 

 one of the large branches near the ground was cut and the liquids poured on, 

 resulted similarly, showing marked injury from the sodium arsenite and carbon 

 bisulphid, on the cut side especially, and none from kerosene and chromic acid. 

 Very little injury was noted on the sumac or locust from any treatments. In 

 1908, when various substances were applied through the cut ends of branches, 

 oxalic acid was found to penetrate and kill the wood and leaves quicker than 

 any other substance tried. 



The problem of weeds in the "West, L. H. Pammel (Confrib. Bot. Dept. Iowa 

 State CoL, 1911, ^0. //.'/, jtp- H-J,6, pis. 8).— This is a record of the author's 

 personal observations on the geographical distribution of certain weeds in 

 portions of the United States and Canada. 



Near the Canadian boundary line "{Eleagnus argentea) spreads rapidly where 

 the surface of the soil has been removed, very much as the Cottonwood does 

 in Iowa or in other parts of northern United States. 



" In the country from Winnipeg to Vancouver and the Rocky ^Mountain 

 States, squirrel-tail grass {Hordeum jtihatnm) is one of the most striking weeds 

 in fields and waste places. It is, of course, a striking weed also in Iowa, but 

 it was rare here prior to 1876. . . . The wild oats (Avena fatua) is common in 

 the Northwest as it is in parts of Minnesota and the irrigated districts of the 

 Rocky Mountains, largely because the weed is spread with the culture of oats. 

 The holy grass (Hierochloe horealis) a well-known native grass of the North 



