long time without auy seeds being produced. Of those plants 

 generally kuown as weeds, there are iu Britain upwards of a 

 hundred species which obtain their uutrimeut from the land 

 prepared by the farmer, and which are plentiful enough in 

 some parts of the country to be hurtful to his crops ; about 

 thi'ee fourths of these are annuals, most of which produce a 

 very large number of seeds. An average plant of the 

 common poppy will yield twenty flowers with 300 seeds in 

 each ; shepherd's purse which runs on to three generations a 

 year, 800 flowers with twenty seeds each at one generation, 

 or 50,000 seeds a year; Chenopodium album 20,000 one 

 seeded flowers; Broomrape 5000 seeds, and most of the 

 others, many thousand seeds to each generation. These 

 annuals can only be attacked whilst the crops are in progress, 

 and the figures quoted will give an idea of how rapidly they 

 increase if allowed to seed. An interesting but small set of 

 annual weeds are the parasites, especially the broomrape and 

 clover dodder ; the former springs up from the ground and 

 remains attached to the root of the clover ; the latter springs 

 up from the ground and fastens upon the clover by its suckers? 

 and increases very rapidly ; neither have leaves of their own 

 but di-aw all their sap from the plant they feed upon. The 

 biennial weeds are not numerous, and can be attacked when 

 the corn crops are down. A small number of perennials with 

 creeping roots, especially Scabous, Sowthistle, Coltsfoot, 

 Fieldthistle, Bindweed, Marestail, and Couchgrass, are very 

 troublesome, and should be rooted out thoroughly at any 

 pains, as they spread to a great depth below the surface and 

 increase fast. New weeds are not easily introduced; the 

 only two which have been diffused widely during the last 

 generation are Veronica Buxbaumii and the Clover dodder. 

 Only about ten of the weeds are directly hurtful to man or 

 beast, from the acrid or narcotic qualities of their fruits or 



