Chapter V — 61 — Types of Areas 



Corsica — 58 per cent, Madagascar — 66 per cent, New Zealand — 72 per 

 cent (1,000 species), Hawaii — 82 per cent, and St. Helena — 85 per 

 cent. 



In other cases, however, endemic species — or, more frequently, 

 units of a lower order, such as subspecies, varieties, forms — are charac- 

 teristic of younger portions of the earth's surface. Then the endemism 

 has an entirely different, more recent origin. This may be the case, 

 for instance, when within the limits of some natural region, due to 

 changes in ecological conditions, an initial form gives rise to new forms. 

 The latter may be closely bound, due to certain specific habitat condi- 

 tions, to this region only, or for some other reason they may remain 

 within the given region and not spread beyond its confines. 



A similar origin of endemics of this type is observed also in case 

 of the relatively recent isolation of a given region. A very striking 

 example of this is the Crimean Peninsula, which at one time constituted 

 part of the eastern Mediterranean region, being connected as late as the 

 Pleiocene period with Asia Minor and Transcaucasia, but which later 

 separated from them and became attached to the South Russian main- 

 land. Because of the fact, however, that the isthmus by which it is 

 attached is still characterized by solonchak soils unfit for the growth of 

 most plants, the Crimean Peninsula is, in a biological sense, almost an 

 island, having at a comparatively recent date entered into a condition 

 of isolation. Consequently, in the Crimea ancient, rehc endemism is 

 represented by only a few species, the number of which, as further 

 studies are made of the flora of Asia Minor, becomes less and less, while 

 secondary endemism, of more recent origin, becomes more and more 

 extensive, embracing ever new forms and species, as we study the flora 

 of the Crimea more thoroughly. And this holds true not only as re- 

 gards the flora but also as regards the fauna of the peninsula (Wulff, 

 1926). 



As a similar example we may take Cape Colony, which, as regards 

 climatic conditions, is entirely isolated from the adjoining parts of 

 Africa and, hence, very rich in endemics of comparatively recent origin. 

 The same holds true in Western Australia, which is cut off from the 

 other parts of Australia by a desert zone. 



Such data forced Engler (1882, Vol. H, p. 48) to point out that 

 "it should never be forgotten that there are two kinds of endemism — 

 one based on the preservation of ancient forms, which may have origi- 

 nated in entirely different regions, and the other based on the develop- 

 ment of new, entirely autochthonous forms". Likewise Braun- 

 Blanqxiet (1923, p. 223) is correct when he states that: "The study 

 and precise interpretation of the endemism of a territory constitute the 

 supreme criterion, indispensable for arriving at any conclusions regard- 

 ing the origin and age of its plant population. It enables us better to 

 understand the past and the transformations that have taken place; 

 it also provides us with a means of evaluating the extent of these 

 transformations, the approximate epoch when they occurred, and the 

 effects which they produced on the development of the flora and the 

 vegetation". 



For these two kinds of endemism different authors have adopted 

 different names. Drude (1890) calls them relic and secondary endem- 



