118 III. INTRODUCED SPECIES. 



1. Abbreviations in First column : — nat. native. — pos. possibly in- 

 troduced — pro. probably introduced — cer. certainly iutroduced. 



2. Numerals in Second column : — The number of local catalogues 

 in which the species is marked as native— dubiously native — introduced 

 — or omitted (0). 



3. Abbreviations in Third column: — nat. native — dub. dubiously 

 native — pos. possibly introduced — cer. certainly introduced — exc. to be 

 excluded — or ... absent. 



In addition to the plants included in the two lists 

 above given, there are stiU some other slightly distrusted 

 British species, which are almost invariably accounted 

 true natives with reference to Britain generally, though 

 questioned locally. They exhibit some faint indications 

 of a foreign origin by being usually seen in cultivated 

 ground, on artificial mounds and rubbish heaps, by way- 

 sides and frequented places, or in the vicinity of houses. 



