210 THE Is^ATURAL HISTORY RETIEW. 



in the country, one mu«t inevitably expect a failure in endeavouring 

 to introduce it." 



In recent days, a few attempts, made with more judgment and 

 perseverance, have met with rather better success, but only in the 

 case of aquatic plants propagated by their rhizomes. Three of these 

 appear to be more or less established : Aponogeton distacliyon in the 

 Lez at Lavalette, planted in 18B8 ; Acorus calamus in the pool of 

 Grramont, planted in 1849 ; and Jussieua grandiflora, thrown into the 

 Lez many years since, and now spread all along its course from 

 Pont Juvenal downwards. 



The indirect or involuntary agency of man has been here, or 

 elsewhere, much more effective in the introduction and naturalization 

 of new species. This takes place by the natural propagation and 

 dispersion — 1, of plants cultivated in fields or gardens ; 2, of weeds 

 or other plants whose seeds have been sown with imported grain 

 or cast aside in picking it ; 3, of seeds imported with wool, ballast, 

 or other substances spread out or heaped up on waste places. 



The escapes from cultivation permanently established in the 

 neighbourhood of Montpellier during the three centuries, have been 

 remarkably few. Of the numerous species cultivated in the botanic 

 garden since its establishment in the eighteenth century, although 

 several have spread as weeds within the enclosure, and five have even 

 extended beyond, two only — Hypecoum procumhens and Veronica 

 peregrina — have become really naturalized in the neighbourhood, and 

 those to no great distance. Besides these, the only cases within the 

 region which Dr. Planchon has been able to ascertain, are those of 

 Cyclamen hedercEfolium, established for the last century at Chateaubon, 

 near Montpellier, but which has not passed the limits of the park ; 

 and of (Enothera biennis, now scattered here and there along streams 

 and in sandy places, but whether escaped from local gardens, or 

 gradually spread from other parts of Erance, where it had been 

 similarly introduced, is uncertain. 



The weeds of cultivation of ancient introduction are undoubtedly 

 numerous ; but the additions within the last three centuries are 

 limited to six species, viz., Amarantus alhus and A. retroflexus, Xan- 

 thium spinosum and X. macrocarpum, Erigeron canadense^ and Bidens 

 hipinnata, all (except, perhaps, Xanthium macrocarpum) of American 

 origin, and all now abundant in vineyards and other cultivated and 

 waste places. Of these, the Erigeron, the Bidens^ and the Xanthium 

 spinosmn, appear to have been first noticed in the last century, the 



