THE AXCIENT AXD MODERN ELORAS OE MONTPELLIEE. 205 



modifications of the Flora, and tlie inquiry into the various causes 

 which have produced these changes. In the following chapters, how- 

 ever, the two questions are combined, and the subject matter 

 divided into two parts, 1. the destruction or disappearance of old 

 species, and, 2. the introduction of new ones. The region which he 

 takes as the field of his observations is defined as limited by the 

 Herault on the west, and the Yidourle on the east, a breadth of 

 about 30 miles, and as extending between 40 and 50 in length 

 from the seaboard on the south, to the mountains of Esperou and 

 Aigoual on the ridge of the Cevennes, which bound on the north that 

 hot, botanically rich, district known under the name of the region 

 of Olives. 



The causes of destruction the most striking to the casual 

 observer, and which would a priori appear to be the most effective in 

 a region like that of Montpellier, where the cultivator and the bota- 

 nist have been equally at work during the three centuries in ques- 

 tion, are the defrichements or breaking up and bringing under culti- 

 vation of old woods, pastures, and wastes, and the extirpation of rare 

 species by the collecting zeal or wanton rapacity of botanists and 

 dealers ; but a closer observation shows that neither of these causes 

 have had the effects popularly attributed to them. Cultivation, 

 observes Dr. Planchon, can only be a cause of destruction to species 

 occupying a very limited area. " It is a difficult matter," he continues, 

 " to extirpate a plant from a country where it is well established. 

 "Wherever it occupies an area of any extent, it always finds some 

 points which suit it, where it can maintain itself, and from whence it 

 can take advantage of the first favourable opportunity for reinvading 

 its ancient possessions." 



These observations, applied generally by Dr. Planchon, are more 

 peculiarly applicable to the Montpellier districts. That the advance 

 of agriculture during the last three centuries has been comparatively 

 slow, is proved by the study of Olivier de Serres' Theatre d'Agricul- 

 ture, published at the close of the eighteenth century, and still a 

 standard work for that country. Deep ploughing, rotation of crops, 

 drill sowing, clearing the banks and borders of fields, and other 

 devices, practised in central and northern Europe, for giving to the 

 objects of cultivation exclusively the beneficial possession of the soil, 

 are scarcely yet brought into bearing on the arable lands of Lower 

 Languedoc ; and nowhere else, perhaps, do the cornfields teem with 

 such a variety of De CandoUe's " plantes cultivees malgTe la volonte 

 de I'homme." The draining of large tracts of bog, to which [>o much 



