250 



Weeds. 



often found in cultivated grounds in this locality, but it is an excellent 

 example of a quick-growing weed, as is indicated by the following 

 instance: One or two plants appeared in a certain garden. The owner 

 wishing to obtain good specimens for his herbarium, allowed them to 

 grow a few days longer that flowers and fruit might be shown by the 

 specimens. When visited again more progress had been made than 

 was expected, and a few heads had already dropped their seeds. The 

 plants were taken, and on the supposition that the seeds dropped 

 would not germinate till the next spring, no further attention was 

 given the matter. But a few weeks later, the owner of the garden 

 happening to pass the place where the groundsel plants had grown, was 

 surprised to find a plentiful crop of groundsel plants already mature 

 and shedding their seeds. This was the second crop of the season 

 and, with the rapid growth, indicates considerable capability for mis- 

 chief in the groundsel. It is this ability to grow quickly that enables 

 some weeds to spring up later than our cultivated plants, and yet soon 

 to overtake and then surpass them in the race of life, and thus become 

 injurious. 



The capacity of a weed for mischief is often greatly increased by its 

 ability to produce a great number of seeds. On an herbarium speci- 

 men of shepherd's purse of ordinary size, I counted sixty-five pods or 

 seed vessels. There were twenty-two seeds in one of these. Supposing 

 all the pods to have been equally furnished, the number of seeds pro- 

 duced by this plant would be 1,430. At the same time all the branches 

 were yet terminated by tufts of flowers, the foundation for many more 

 pods. One thousand seeds would be a very moderate number to be 

 ascribed to one of these plants. The burdock, which has some reputa- 

 tion as a troublesome weed, and which is a much larger plant than the 

 shepherd's purse, is much more easily controlled and much less to be 

 dreaded, because its capacity for seed production is much less. The 

 purslane produces numerous seeds, and this character, added to its te- 

 nacity of life, makes it a very formidable foe in gardens. 



But not only the number of weed-seeds is a factor for mischief, 

 but also their longevity. Some seeds, when buried in the soil 

 too deep to germinate, retain their vitality many years, and if they 

 are brought to or near the surface after lying dormant a long time, 

 they revive and grow. In this way, the sudden and mysterious ap- 

 pearance of certain weeds in fields previously free from them is easily 

 explainable. To this cause also the constant recurrence of weeds after 

 careful efforts to exterminate them may be attributed. It is recorded 

 that in a comer of a certain garden a single stramonium plant (Datura 



