in. INTRODUCED SrECIES. 71 



in them will usually be found connected witli some want 

 of capacity for correct reasoning, or with some superfi- 

 ciality of judgment, betrayed by inconsistencies and false 

 reasoning in regard to other matters also. This was 

 notably the case with the late Dr. Broiu field ; who 

 evinced a very decided bias for pronouncing plants to be 

 true natives, either on slight grounds only, or even 

 against strong reasons for doubt. And while he was 

 rather remarkable for a good store of miscellaneous 

 knowledge about details, that estimable botanist was 

 slenderly endowed with the capacity for sound reasoning. 

 The views of various other English botanists will be 

 shown more in detail some pages forward, reduced into a 

 tabular list. 



2. Examples in illustration. 



In former volumes of this work the grounds for doubt- 

 ing the nativity of species were occasionally stated ; 

 though they were seldom entered upon in much detail. 

 It was usually found impossible, within any moderate 

 space of text, to examine in detail the various reported 

 localities for doubted plants, and to consider what rea- 

 sons there might be for deeming them insufiicient evi- 

 dences of true nativity. Some further intimations of the 

 like kind may usefully find place here, by selection of a 

 few species for remark in connexion, whereby to render 

 them in some measure reciprocal compai'isons and illus- 

 trations. 



1. Corn-field plants. — Numerous weeds occur among 

 corn and other crops, or elsewhere on ground worked and 

 turned over by human industry. Some of these appear 

 to be merely casual stragglers, seen once or twice in a 

 spot, with no certainty of being again met with in the 



