232 THE POPULAR SCIENCE MONTHLY. 



tries, we pass through, regions occupied by like series of vegeta- 

 tion. Pursuing our course from north to south, we find the beech 

 giving place in lower latitudes to varieties of oak ; and it is one 

 of the effects of this movement that other oaks appear at first in 

 scattered colonies, as does also the chestnut, which, aside from its 

 requirements as to the composition of the soil, seems to find, espe- 

 cially in southern Europe, the conditions normal to its forest 

 development. The association of foliage-trees, whose outline is 

 thus sketched, which would cover central Europe with a continu- 

 ous forest if the continent had not been taken possession of by 

 cultivation, is found on the southern slopes of the great mountain- 

 ranges, only under specially favorable conditions of altitude and 

 moisture. Its principal characteristics, besides the particular 

 grouping of species, result from the winter caducity of the leaves, 

 to the law of which the holly, the box, and the ivy — types also be- 

 longing to the next southern or Mediterranean group — are almost 

 the only exceptions. 



The Mediterranean group touches abruptly on the preceding 

 one, and derives its name from the Mediterranean Sea, of which 

 it occupies the whole periphery. In all the regions within this 

 perimeter a similar forest flora covers with the same species a 

 soil generally hilly, under a climate dry and warm, while subject 

 to violent contrasts. The evergreen oaks, other oaks with semi- 

 persistent foliage, the laurel, olive, pomegranate, terebinths, some 

 of the maples, the oleander, and the carob ; numerous shrubs with 

 persistent leaves — laurestinuses, arbutuses, mock-privets, daphnes, 

 heaths, cistuses, etc. — contribute to the constitution of this assem- 

 blage, which is all the more striking because an astonishing rich- 

 ness of characteristic details is concealed in it under an apparent 

 uniformity. A more careful examination of the elements of which 

 this flora is composed is demanded if we undertake to seek their 

 origin. Besides the foliage-trees, the group includes conifers 

 which are j)eculiar to it. The pines alone cover a large extent, 

 one of them, the Aleppo pine, being very generally diffused, while 

 a number of other species have each their determined station and 

 place. The mountains in the interior of the region bear species 

 that are special to them, and it is to such scattered islands of vege- 

 tation that we are indebted for such choice garden-plants as the 

 spruces of Andalusia, Numidia, Mount Parnassus, Cephalonia, 

 and Cilicia. In the same category are the cedars, which, with 

 different names and varietal distinctions, people the ridges above 

 a certain level of altitude of the Taurus, Lebanon, and Atlas. 

 These are the mountaineer conifers, adapted to the Alpine stations 

 of the Mediterranean region, where the altitude permits the beech, 

 chestnut, maples, lindens, and birch to reappear and maintain 

 themselves here and there in sporadic colonies. 



