Page:Transactions of the Natural History Society of Northumberland, Durham, and Newcastle-upon-Tyne (1867).djvu/128

110 well-established plants which yet are likely to have been introduced by horticulture by the name of Denizens. Of the first class we have examples in the poppies, fumitories, Chrysanthemum segetum, Centaurea cyanus: of the second in Chelidonium majus, the hellebores, and Saponaria officinalis. The species clearly introduced and not well settled in are called Aliens. These introduced plants have come from various parts of the world. In the Flora of Britain we have instances of American plants which have thus become "naturalised" in Erigeron canadensis, Mimulus luteus, Coronopus didyma, OEnothera biennis, Galinsoga parviflora, and Anacharis alsinastrum. Our four common poppies grow really wild in grassy places, Rheas in Sicily, and the other three in Greece and the Crimea. Centaurea cyanus also comes from Sicily, the common wallflower grows wild upon rocks in Greece, Datura stramonium on the shores of the Caspian, Corydalis lutea, Vinca major, and Petroselinum sativum also in the south-east of Europe. "We have not attempted in this list to trace out the introduced species to their sources, but only to place them in their correct classes of citizenship, so far as the two counties are concerned, as follows:—

1.—The Natives, so far as we can now judge, the aboriginal possessors of the soil.

2 and 3.—The Colonists and Denizens, the well-established importations of the historic period.

4.—The Aliens, importations not fully established.

5.—The Incognita, species to be rejected from the list, either as being extinct or requiring confirmation before they can be claimed with safety.

Types of Distribution.—The readiest means of showing the relation which the Flora of any county or province of Britain bears to that of the whole island is furnished by Mr. Watson's classification of the species under their "types of distribution" as follows, viz.:—

1. British Type.—Species which are more or less generally diffused throughout the whole or nearly the whole of Britain.