Dirr^roy of botant 839 



SESSIONAL PAPER No. 16 



Two boards, each perforated by a number of 1-inch holes, of the length of the 

 intended pit, were nailed together at an angle so as to enclose a space between them. 

 They were then placed on the ground, the air-space between them serving for the 

 purpose of ventilation. The boards and ground over the area to be occupied by the 

 pit were then covered with a layer of straw 1 foot deep. The potatoes were piled 

 thereon, forming an angular ridge. They were then covered with another layer of 

 straw about 6 inches thick, a beam of about 8 inches in thickness was laid on the 

 top of the ridge and the whole covered with another layer of straw and about a foot 

 of soil then placed all round. After the whole heap had been allowed to settle properly 

 the beam was carefully pulled out from the end and another ventilation tube resulted. 

 Both ends of this tube were plugged with a bmach of straw to be opened or closed 

 as the temperature of the pit required. The temperature of the pit was taken daily 

 by means of a self-registering thermometer which could be let down on a string through 

 a small wooden tube to about the centre of the pit. There was no heating of the pit 

 nor any frost recorded by the thermometer. The temperature outside the pit dropped 

 some 30° F. below zero, and a good many iDotatoes on the outside of the pit were found 

 to have been touched by frost, but none were found to show anything like the storage 

 rots which were present in the cellar and root-house. The experiment seems worth 

 repeating. This form of pit may prove of value in a good many districts of Canada 

 where the temperature does not go so much below zero, and it has the advantage of 

 being of a very simple construction. 



III.— ECONOMIC BOTANY. 



GENERAL CONSIDERATIONS ON WEEDS. 



In order to be in a position to deal with the question of weeds in a proper and 

 scientific manner it is obvious that the more one knows about the weed and its man- 

 ner of growth the better fitted will cue be to combat it. In some of the older countries 

 of the world a good beginning has been made, such as, for example, the work of 

 Fruwirth in Germany. But this is a problem that each country must work out for 

 itself as the mode of life of any particular weed is by no means the same in all coun- 

 tries. It frequently happens that when a species of weed is introduced from one 

 country to another it spreads more rapidly and is much more troublesome than it 

 was in the parent country. It is evident, too, that in a country like Canada, where 

 there is great diversity of climatic conditions, any investigations which ai^ to be of 

 value would require to be carried out in several provinces of the Dominion. As indi- 

 cating lines along which investigations might profitably be conducted, the following 

 are some of the more important headings on which complete information seems 

 desirable : — 



(1) Whether the particular species of weed is a native of Canada or has been 

 introduced from some other country. If introduced, the manner of its introduction 

 should be known as far as possible and whether it is still being introduced among 

 farm or ^-arden seeds at the present time. 



(2) Its geoigiraphical distribution in the provinces of Canada. 



(3) Its relation to soils of various kinds. It is well known that some weeds have 

 a decided preference for a limy soil, others prefer a soil in which lime is almost 

 entirely absent, while there are others which will grow equally well on either. 



(4) Its relation to the various crops grown on the farm. Some weeds thrive best 

 <)n tilled land while they disappear or at least are held in cheek if a hay crop be 



Ottawa. 



