VI. NATIVITY OF SPECIES. 61 
an Appendix List; as also the few species supposed to have 
become extinct, and most of which perhaps were Casuals only; 
and those improperly recorded as British species, through errors of 
name or mistakes about the localities of garden examples, or con- 
sequently on tricks and impositions practised by guides and others 
at the expense of incautious botanists. Typographical convenience 
will necessitate a somewhat strict adhererence to this rule; the 
adopted formula of seven lines of text just allowing four species to 
a page without break or division. It would be scarcely possible, 
and little useful if possible, to exhibit the distribution of the 
Aliens and Casuals in the same form. The definition and use of 
the three terms may be thus understood :— 
1. Native. — Apparently an aboriginal British species; there 
being little or no reason for supposing it to have been first intro- 
duced into this island by human agency. Eaamples may be cited 
in Corylus, Calluna, Clematis, Brilis, Butomus, Teesdalia, Glaus, 
Littorella. 
2. Denizen.—At present maintaining its habitats as if a native 
species, without the direct aid of man, but liable to some suspicion 
of haviug been originally introduced by human agency, whether 
by design or by accident. The single species of Aconitum, Cheli- 
donium, Saponaria, Myrrhis, and Buxus, well established in some 
of their localities, are perhaps not clearly native in any of them, 
and certainly introduced to several of them. 
3. Colonist.— A weed of cultivated land, by road sides or about 
houses, and seldom found except in places where the ground has 
been adapted for its production and continuance by the operations 
of man; with a tendency also in some of them to appear on the 
shores, landslips, and in what are called “ waste places.” Ranun- 
culus arvensis, Papaver dubium, Thlaspi arvense, Centaurea Cyanus, 
Alopecurus agrestis ave weeds of cultivated land, and would 
perhaps disappear if plough and spade ceased their work. Several 
Chenopodia, Mercurialis annua, Rumex pulcher, Lepidium ruderate; 
Asperugo procumbens, and others constitute connecting links be- 
tween the Colonists and Denizens, found chiefly by road sides, 
rubbish heaps, dunghills, and near the sea. 
