comparati\(' viciousness of weeds, a scale of twent_y points has been 

 constructed, with i\xo j^rados nndcr each point, making a total of one 

 hundred as the niaxinnmi tor the worst weed. The i)oints and 

 methods of grading may be briefly ilhistrated as folloAvs: 



(1) Recof/nition of the seed. — The seed of quack ^rass is distin- 

 g-uished with threat difficulty and is therefore put in i>Tade 5, while 

 that of sorrel, being less difficult to distinguish, is put in grade ."5. 



(2) Separation, of the seed. — The seed of dandelion being quite 

 difficult to separate from desirable seed, is graded as i, while that of 

 purslane can be easily separated and is hence put in grade 1. 



(8) Reeognition of the weedj plant. — Weed plants vary greatly, 

 especially as to the characteristics which distinguish them from use- 

 ful plants. Canada thistle, which is graded 4, is much less easily 

 recognized than the dandelion, which is put in grade 1. 



(4) Prevalenee. — The scarcity or abundance of a particular variety 

 of weed in a given locality largely determines the amoiuit of damage 

 which it does. In this respect, for example, Canada thistle is a worse 

 weed in some localities than dandelion. 



The other points in the scale are as folloAvs: 



(5) Ability to rob the soil: (0) Seed-prodncing capaeity ; (7) Dis- 

 seminating power; (8) Vitality of the seed; (9) Longevity of the 

 plant; (10) Root and stem propagation; (11) Poisonous or other 

 obnoxious qxialiti.es; (12) Forage value; (13) Resistance to methods 

 of eradication ; (14) Aggressiveness; (1,5) Harboring injurious fungi; 

 (16) Harboring injurio^is insects; (17) Relation to soil; (18) Rela- 

 tion to dim ate; (19 and 20) Miscellaneous. 



The result of marking weeds according to this scale is illustrated 

 in a table for eight different kinds of weeds. Canada thistle rates 

 74 in badness, ox-eye daisy G4, quack grass 54, narrow plantain 43, 

 sorrel 38, and toad-flax (butter and eggs) 31. This method of mark- 

 ing is, of course, subject to revision and must be varied considerably 

 for ditferent localities. 



The bulletin also contains a set of questions with reference to 

 weeds, addressed to farmers and gardeners for the purpose of secur- 

 ing infoi-mation which may lead to the establishment of principles 

 for cleauei- cuhure in future and to legislation against weeds. 



BULLETIN' No. .i:!. :\rAKCn 2B, 18S9. 



Prices of nitrogen, rirosmioRic acu), and roTAsii, G. II. Cook, 

 LL. D. (pj). 2, 3). — This contains the schedule of trade values adopted 

 by several experiment stations for ISSi) and explanations of the prac- 

 tical use of these xalues. 



r.lLLETIX No. .-.4, MAliClI 27. 1889. 

 Potash as a fkrtilizkr. K. B. Vooriiees, M. A. (i)p. 2-11). — 

 '• Field experiments with fertilizers have been an important feature 

 of this Station's work since its establishment in 1880." The main 



