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great abiiudance. The seeds of some annuals when buried in the soil retain 

 their vitality for long periods. Mustard seed, for instance, has been known 

 to lie in the soil for a quarter of a century and then when placed in a 

 favorable en-^-ironment, grow into vigorous phints. In this class we have 

 such common weeds as dodder, foxtail, smart\^eed, Russian thistle, crab- 

 grass, pigweed, lamb's quarters, dog fennel, barnyard grass, tickle grass, 

 bracted plantain, ragweed, corn cockle, night-flowering catchfly, mustard 

 and whitetop. 



Buckhorn. 



Biennials are those plants which spring from seed and produce only a 

 <*Iuster of leaves the first season. In these leaves are manufactured and 

 stored large amounts of ])lant food for use during the second season of 

 growth. During tlie second season, a flower stalk is sent up and many 

 seeds formed, after which the plant dies. This group depends on seed for 

 propagation. Here belong wild carroty \yild sweet clover, burdock and com- 

 mon evening primrose. 



