14 INFLUENCE OF CLIMATIC AND GEOLOGICAL CHANGES 



been already shown that the Mediterranean must have had 

 communication with the Atlantic since the Miocene Age. Sir 

 Joseph Hooker and his companion, the late Mr. J. Ball, in their 

 " Spilegium Florae Maroccanae " show very distinctly that of 

 820 species of the great Mediterranean Flora which extends from 

 the Indus to the Atlantic Islands, 96 are common to Spain and 

 Morocco. Of these nearly all are found in the neighbour- 

 hood of Tangiers and Tetuan. They succeeded in making a 

 very large collection of plants, and among them a considerable 

 number of new species in the area of the Great Atlas, but no 

 new genera. The most singular point in Sir Joseph Hooker's 

 opinion about the Great Atlas flora was the presence of a 

 large number of the common species of Central Europe, 

 coupled with the fact that they were unable to adapt themselves 

 to different climatal conditions, and that many of them have no 

 nearer habitation than the mountains of Central or Southern 

 Spain. He found in the northern extremity of Morocco 

 together with the Mediterranean flora the infusion of another 

 element, which he denominated the Peninsula flora. Its limits do 

 not seem to extend more than 30 or 40 miles south of Tangiers 

 and Cape Spartel. Nearly all the 96 species mentioned above 

 are common exclusively to Morocco and Spain, having been found 

 in the neighbourhood of Tangiers and Spain. He sums up his 

 interesting preliminary observations on the flora of Morocco thus : 

 " The conclusion to which I am led by a consideration of the 

 facts, is the same that I have derived from rather long 

 observations of the mountain vegetation of Central and 

 Southern Europe, namely, that it is impossible to explain the 

 facts without admitting that a large portion of our present 

 flora is relatively very ancient, and that the species had assumed 

 their present characters at least as early as the Miocene 

 Epoch." 



The discovery last year si Erica lusitanica, Spartina Townsendi, 

 and Seiaria verticillata growing wild in this county is of special 

 interest on account of their association with the Peninsula 

 flora. 



