34 BULLETIN 521, U. S. DEPARTMENT OF AGRICULTURE. 
Lesson 58. — Weeds — Continued. 
1. Relation of weeds to cultivation. 
2. How weeds spread. 
3. Method of eradication. 
Illustrative material: Charts showing how some weeds spread. 
Lesson 59. — Important Local Weeds. 
1. Their botany. 
2. Methods of control. 
Illustrative material: An herbarium of local weeds; a collection of 
seeds of noxious weeds. 
Special references. — The following Farmers' Bulletins : 86, Thirty Poi- 
sonous Plants ; 188, Weeds Used in Medicine ; 279, A Method of Eradi- 
cating Johnson Grass; 368, The Eradication of Bindweed or Wild 
Morning Glory; 382, The Adulteration of Forage Plant Seeds; 464, 
The Eradication of Quack Grass; 545, Controlling Canada Thistles; 
660, Weeds and How to Control Them. 
Exercise 35. — Collection and Study of Weeds. 
Purpose. — To familiarize students with the common noxious 
weeds. 
Directions : Each student should be requested to collect and iden- 
tify 10 weeds. It is preferable that these weeds be brought from the 
home farm and represent the weeds giving most trouble. If the 
students have had work in systematic botany a botanical key may be 
used for identification. Other students may use an illustrated weed 
manual. From the weeds collected specimens may be selected and 
mounted as a weed herbarium for the agricultural museum. Such 
an herbarium will be useful for identifying weeds in the future as 
well as for study when fresh specimens are not obtainable. When- 
ever possible a sample of ripe seed should accompany the dried plant. 
Record and report: A brief description should be given of each 
weed with an explanation of why it is pernicious and how it may best 
be controlled. Wherever possible a drawing should be made of the 
plant when very young. 
Exercise 36. — Testing farm seeds for impurities. 
Purpose: To gain practice in the examination of purchased seed 
and further practice in the recognition of seeds of grasses, legumes, 
and weeds. 
Directions: Samples of alfalfa, the clovers, and the grasses should 
be tested by each student for impurities. If the seed sold on the 
local market does not give the desired practice the instructor should 
make up mixtures of good seed containing foreign matter and seeds 
of weeds. Complete directions for this work may be obtained from 
Farmers' Bulletin 428, Testing Farm Seeds in the Home and in the 
Rural School. 
Record and report: A record should be made of the impurities 
found in each sample which will form the basis of a report showing 
the relation of the foreign material to the value of the seed. 
