BOTANICAL FEATURES. 39 
appear so, but introduced into the district either directly or indirectly 
through the instrumentality of man. These, again, may be divided 
according to their various degrees of wildness, so that the whole 
vegetation of the place will fall into certain grades of citizenship, so 
to speak, which, following the arrangement of the !ate H. C. Watson, 
are commonly classed as follows :— 
Natives.—The aboriginal occupants of the soil. 
CoLonists.—Weeds of cultivated land in general, mostly found 
where the ground has been rendered favourable for their 
growth by the operations of man. If cultivation ceased, these 
would probably disappear altogether in course of time. 
DENIZENS.—Plants having all the appearance of being really 
native, but which are either known or suspected of having been 
introduced into the locality by human agency. These would 
probably continue to hold their footing even if man became 
extinct. 
ALIENS.—Plants certainly known to be of foreign origin; less 
thoroughly established than Denizens, and in many cases 
fugitive in their stations. 
CasuaLs.—Chance stragglers from cultivation, not likely to become 
permanently established, garden outcasts, and foreign plants 
occasionally imported or sown with agricultural seeds, or 
introduced with ballast. 
In almost every area certain species might be located equally 
well under one or other of these divisions, especially the last two, 
because no hard-and-fast line can be drawn between them; more- 
over, a plant which is unquestionably native in one part of the 
country may be no more than a mere Casual in another. The 
principal point, however, is to avoid placing on the same level as 
true Natives those plants which are properly merely Aliens or 
Casuals. It matters little how many of these foreign forms are 
recorded in a local flora (the information may be very useful some 
day) provided they are distinguished as such ; but, for all purposes 
of analysis and comparison, only the first three classes—Natives, 
Colonists, and Denizens—should be taken into account. And, 
again, plants known or believed to be extinct should be excluded 
from Tables and Summaries used in comparing local Floras, because 
our knowledge of extinct species must necessarily depend upon old 
records, whether printed or manuscript lists, or else collections of 
preserved specimens; and, where such evidences are wanting for a 
particular district, nothing can be known about the plants which 
used to exist there. 
An analysis of the Guernsey flora, as recorded in these pages, 
