Extirpation of IVeeds. 635 



Annuals are those which continue only one year, the plant dying after perfecting 

 their seeds: these are generally very prolific in seeds. 



Biennials are those which continue two years, and die after perfecting their seeds 

 the second year : these are also prolific in seeds. 



Perrennfals are those which continue many years ; some of these perfect their 

 seeds every year, and others being very tenacious of growth by their roots, and 

 having the faculty of reproducing themselves in this way, are less prolific in seeds; 

 but many of them increase both by roots and seeds. 



A list or catalogue of weeds, or plants injurious to cultivation, formed by a per- 

 son whose observations have been chiefly confined to a local spot, must evidently 

 be imperfect, as many kinds common and noxious in other places may be unob- 

 served there, and omissions will be the consequence; this may be, in some measure, 

 the case with this Paper, for though the writer of it has seen many other parts of 

 the kingdom than his own neighbourhood, yet he may not have examined them 

 particularly enough to be minutely acquainted with their spontaneous productions; 

 additions will therefore be wanting from observations made elsewhere. 



The following is a list of weeds or plants injurious or noxious to cultivatioHj 

 or cultivated land, principally observed by the writer hereof, growing in 

 I. Gardens, 

 II. Corn-fields, 



III. Meadows and pastures, 



IV. Waste and uncultivated land, 

 V. Hedges, 



VI. Woods and plantations; 

 with some observations on their injurious tendency, methods of extirpation, and 

 instruments made use of for that purpose. 



I. Garden IVeeds, are, 



1. Couch grass, or, as here called, squitch; the roots of the hardy perrennial 

 grasses, extremely tenacious of growth ; they are the dog's grass (Triticum re^jcnij, 

 the white bent grass (Agrostis alba), and the tall oat grass (Avena elatior). The dis- 

 tinction between these grasses is very observable in their flowering stems, and in 

 the ears or awns containing their seeds, which are as separately dis;inct as those of 

 the different kinds of grain; moreover, the latter (Avena elatior) has a bulbous 



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