Linmean Society. 467 



Alegre. while others range still further south to Monte Video. On 

 the other hand, the comparatively small number of Melastomaceee, 

 and the abundance of herbaceous and half-shrubby Verbene<E in Rio 

 Grande, indicate the approach to the Argentine region. The con- 

 siderable diiFerence between the vegetation of Porto Alegre and of 

 the northern shore of the Plata, Mr. Bunbury conceives to be due to 

 climate alone ; and the fact mentioned by M. Auguste de St. Hilaire, 

 that the cultivation of mandiocca and sugar extends as far south as 

 Porto Alegre, and no further, seems to point it out as the southern- 

 most limit of the seasons of tropical Brasil. 



For a comparison of the Flora of Chile with that of the Argentine 

 region, Mr. Bunbury regrets that he has not sufl5cient materials. 

 Meyen indeed states, that Chile, and the countries on the eastern 

 side of the Andes in corresponding latitudes, cannot be considered 

 as separate botanical regions ; yet the information which he himself 

 gives as to the Chilian Flora, seems to show that its general phy- 

 siognomy is very different from the Argentine. The accounts of 

 many travellers show the climate and soil of Chile to be much more 

 dry ; and the Chilian Flora appears to be as strikingly characterized 

 by dry shrubs with coriaceous and glossy leaves, as that of the Plata 

 by the prevalence of herbaceous forms. In the abundance of Myrtles, 

 indeed, and of shrubby and arborescent CompositcB, the vegetation of 

 Chile may be compared rather with that of Southern Brasil. At 

 the same time the valuable catalogues drawn up by Sir William 

 Hooker and Dr. Walker-Amott show that many remarkable genera, 

 and not a few species, are common to both sides of South America. 



The Argentine Flora has little or no general analogy to that of 

 the parts of North America lying in corresponding latitudes on the 

 other side of the Equator. Yet there are some striking, though in- 

 sulated, points of resemblance. A species of Cephalanthus grows on 

 the shores of the Plata; jEschynomene ciliata, ^'og., is excessively 

 like the North American jE. hispida ; there is also a Pontederia, 

 extremely near to P. cordata, if not a mere variety ; and a Sisyrin- 

 chium, much resembling S. Bemiitdianum. 



The Flora of the shores of the Plata offers an extraordinary dif- 

 ference from that of the Cape of Good Hope, Ipng within the same 

 parallels of latitude, and with nearly the same mean temjjerature. 

 The many points of analogy, and the general physiognomical resem- 

 blance between the vegetation of the Cape and that of New South 

 Wales, have been repeatedly noticed ; but between the botany of the 

 Cape and that of La Plata we find scarcely anything but contrasts. 

 The general physiognomy is different ; in the Cape Flora there is a 

 great predominance of dry, hard, small-leaved shrubs ; and almost 

 all the characteristic families and genera of the one are wanting or 

 insignificant in the other. Almost the only points in the Argentine 

 Flora which strongly remind us of South Africa, are several species 

 of Oxalis, and some gay-flowered Irideee and AmaryllideeE. ITie 

 Cactea of La Plata are represented at the Cape by succulent Euphor- 

 bias ; and the herbaceous and half-shrubby Malvacece by the Her- 

 manniacece. The Flora of Buenos Ayres is also much less peculiar 



32* 



