84 



Fig. 33. 



Prickly Lettuce. 



' Lactuca Scariola, (L). 



Prickly Lettuce is a native of the old world, and has invaded 

 this Province both from New York and Michigan. It is a winter 

 annual ; it springs from seeds in the fall, and survives the winter. 

 The plant grows to a height of 3| feet ; the stem is leafy and usually 

 smooth ; the leaves are oblong, and slightly pointed, often clasping at 

 the base ; the under surface of the midrib of the leaf is spiny : Heads 

 are numerous and yellow. 



Time of flowering, July-September. 



Time of seeding, August-October. 



Dispersal — By means of its seeds, which are provided with a pap- 

 pus or tuft. An ordinary plant may produce 8,000 seeds. 



Eradication. The best methods of destroying the weeds are : 1. 

 To mow repeatedly as it comes into bloom, or earlier ; 2. To cultivate 

 thoroughly with a hoed crop. By this method the weeds in the soil 

 will be induced to germinate. They should not be covered deeply in 

 plowing. Mature plants should be cut down and burned lest the seeds 

 be blown about and scattered by the wind. 



Farmers should be careful to buy only clean clover, millet and 

 grass seeds, and the weed inspector should insist on the fulfilment of 

 the law, and have all fence-corners, roadsides, and waste lands cleared 

 of the pest. 



