We should have four great realms:-(1) Europe and Northern and Temperate Asia, Africa north of the Sahara (palaearctic region) and North and Central America (nearctic region); (2) Africa and South-Eastern Asia (Ethiopian and Indian region); (3) South America (neotropical region); and (4) Australia (Australian region).
At last, in the latest Pliocene strata (often called " pre-Glacial ") we find a flora consisting almost entirely of existing species belonging to the Palaearctic regions, and nearly all still living in the country where the fossils are found.
The flora, however, is essentially Palaearctic, American and.Australian types having disappeared.
The Tegelen plants are mainly north European; but there occur others of central and south Europe, and various exotic and extinct forms, nearly all of which, however, belong to the Palaearctic region, though some may now be confined to widely separated parts of it.
The earthworms of England belong entirely to the three genera Lumbricus, Allolobophora and Allurus, which are further subdivided by some systematists; and these genera form the prevalent earthworm fauna of the Palaearctic region and are also very numerous in the Nearctic region.