18 THE IXDIAXA WEED BOOK. 



Ordinary annuals spring from the seed in spring, mature, blossom 

 and ripen their seeds before the frosts of autumn. Ragweed, fox- 

 tail, purslane and crab-grass are 4 of our worst weeds which are 

 examples of this group. As a rule these summer annuals have 

 small fibrous roots and produce many seeds. 



Winter annuals spring from the seed in late summer or au- 

 tumn, produce a growth of root-leaves before the ground is 

 thoroughly frozen, then in early spring send up a flower-stalk and 

 ripen their seeds usually by May or June. Shepherd's purse, 

 pepper-grass, white-top and prickly lettuce are among our worst 

 of winter annuals, while winter wheat and rye are cultivated ex- 

 amples. Some of these weeds are both winter and summer an- 

 nuals, a part of the seed germinating in the spring and the flowers 

 appearing much later in the season than those of the same species 

 from the winter annuals. 



In dealing with annual weeds the one general and obvious 

 method is to destroy them in some manner before their seeds ripen. 

 This can best be done by mowing, pulling, cutting with the hoe 

 or smothering with the cultivator. If this be kept up for a few 

 years and the work thoroughly done they will be completed eradi- 

 cated from a farm. They would all be destroyed the first season 

 were it not for the fact that the seeds of many species possess 

 great vitality and often remain in the ground for years without 

 impairing their power of growth. When brought close enough to 

 the surface, if the conditions of moisture and temperature are 

 right, they usually sprout at once. Any method of cultivation, 

 especially in late fall or early spring, which will cause these buried 

 seeds to germinate will thus go far towards getting rid of annual 

 weeds, provided, of course, the young ones are killed as they ap- 

 pear. The young plants of ragweed, wild mustard, lamb's quar- 

 ters, black bindweed and many other annuals are easily uprooted 

 and killed by harrowing in autumn the growing crop of wheat, 

 oats or rye with a light slope-toothed harrow. After the crop is 

 well up, and there is no danger of covering the blades too deeply, 

 few if any grain plants will be dragged out if the work is done 

 when the land is in proper condition for harrowing 



BIENNIALS. A biennial is a two-year plant, that is, one which 

 springs from a seed and spends the first season in storing up a 

 supply of nourishment in a large root or tuber, this being used 

 the second season in promoting a rapid growth and producing 

 flowers and seeds. Among our worst biennial weeds are the com- 

 mon thistle, wild carrot, mullen, burdock and hound's tongue. Bi- 



