274 Count Gaston de Saporta on the Temperature 



phalartos, that the Zamites, Ctenis, Pterophyllum, and Nilsonia of 

 the secondary strata most closely approach. And as there is no 

 reasonable doubt that these various genera really formed part of 

 the same group as the existing Cycadese, the habits and distri- 

 bution of the latter in the world of our day may furnish us^ by 

 analogy^ with valuable details as to the state of Europe at the 

 period when these plants grew there, especially if we take care 

 to select as examples those which most faithfully reproduce the 

 ancient fossil types. 



We must therefore compare these principally with Encephalartos 

 and Macrozamia. The species of the former genus inhabit 

 Southern Africa from 20° to 30° S. lat. ; those of the second 

 grow in South-western Australia, about 30° S. lat., and extend 

 as far as 35°. These, therefore, as M.A.Brongniart has pointed 

 out*, are rather subtropical and austral genera than really 

 proper to the equatorial regions ; the same remark is applicable 

 to the species of Cycas and Ceratozamia, which advance in Japan 

 and Mexico far beyond the tropics, to 32° N. lat. The habits of 

 the plants of the group which seem best to reflect those of the 

 fossil Cycadese are indicated by M. Miquel in his monograph of 

 the Cycadesef. He tells us that the species of Encephalartos 

 grow at a considerable distance from the Cape region properly 

 so called, and beyond the limits of the flora characterized by the 

 presence of Proteacese and Ericaceae, under the shelter of a chain 

 of mountains, in a country exposed to the calorific influences of 

 the torrid zone, but without precisely making part of it. The 

 first plants make their appearance about Uitenhage, in very 

 limited stations separated by great intervals. Further on the in- 

 (iividuals become more numerous, especially towards Amatymbis 

 and Tambookis ; they are never met with in the plains, but fre- 

 quent the mountainous districts. Some prefer stony soils ; 

 others seek a rich vegetable mould ; lastly, they do not appear 

 upon naked slopes, but in the midst of thick copses of spiny 

 shrubs. They are nowhere abundant, but disseminated in groups; 

 the mountains which they inhabit attain an altitude of 2000 feet, 

 and are dependent on a chain of which the elevation is not less 

 than 1000 feet, and of which the slope directed towards the east 

 and north pours its waters towards Delagoa Bay. Such is 

 the physiognomy of these plants : a faithful image of a world 

 that has disappeared, they carry us back irresistibly towards the 

 Europe of Secondary times, of which they explain to us the ve- 

 getation and the aspect ; nothing is altered, if we replace with 

 Conifers the Leguminosse and llhamnese of this part of Africa ; 

 but nothing compels us to assume for this epoch a temperature 



* Tableau des Genres de Vegetaux fossiles, p. 59. 

 t Monographia Cycadearum, p. 40. 



