﻿162 J. S. Gardner — On Ettingshausen' s Theory. 



Glancing at the distinctive Mora of the Californian coast-line, 

 we see a series of European genera (although represented by other 

 species), whose origin Ettingshausen states to have been derived, in 

 Tertiary times, from European elements, which elements, being 

 universally distributed, were, however, according to the Baron's 

 theory, also present even at that time in California. As instances, 

 he traces the Californian Quercus Douglasii and Q. agrifolia to their 

 supposed ancestor. The greater the resemblance between different 

 species, the greater the probability that they are derived from a 

 common stock ; as, for example, we see that Liquidamhar styraeifluum 

 and L. orientale are both derived from the Tertiary L. europceum, 

 whilst two other species, closely resembling each other, L. altingia 

 and L. cMnen&e, were derived from another and still unknown 

 ancestor. 



In the phyto-regions of Japan, North America, the Mediterranean, 

 etc., alongside of the chief-elements the collateral-elements have 

 also contributed their share to the character of the vegetation ; 

 whilst in the temperate regions of the Himalayas and Andes they 

 have markedly influenced it. On the other hand, the Cape and 

 Australian Floras owe their pronounced character to a remarkably 

 preponderating development of the chief-elements, although, even 

 here, residua of the collateral- elements are to be traced. As the 

 Cape and Australian Flora-elements are, lapon this theory, derived, 

 not simply from the European, but the universal Tertiary Flora of 

 the temperate regions of the world, they had originally the same 

 composition. At the Cape, plants of an Australian, and in Australia 

 those of a South African character grow. This theory explains the 

 community in the recent Floras of both regions of a number of 

 families and genera, of which the ProteacecB, Ericacece, and half a 

 dozen others, are conspicuous examples. In other natural Floras of 

 the world remains of these elements are also met with as represen- 

 tative genera and species. Thus in the Mediterranean region the 

 Cape-element is seen in the Ericas, species of Mesembryanthemum, 

 and a Pelargonium and Apteranthes (representing Cape Stapelice). 

 Callitris, belonging to the same Flora, is descended from an 

 Australian element. The numerous representatives of the existing 

 Australian-element in the Tertiary Flora of Europe do not indicate 

 that these belong to an older type of vegetation, but simply show 

 the former connexion of these Floras through the Flora-elements, 

 when distant parts of the globe were yet united. 



The Baron then explains that in some regions the Tertiary Flora- 

 elements have come down almost unchanged, and in others have 

 taken special characters, arising from the almost exclusive develop- 

 ment of some only of the Flora-elements, and the expulsion or 

 suppression of the rest. Besides the Tertiary Floras, beds of 

 Cretaceous age have furnished plant-remains. We can trace some 

 of the Flora elements to this period, and prove that in it even simpler 

 elements are contained, which unite in themselves some of the parent- 

 stocks, wliich we have been considering as Tertiary Flora-elements. 



The differentiation of the Flora-elements, commenced, according 



