46j? Liniuean Societij. 



The botanical characteristics of this region are well-marked ; its 

 most striking peculiarity consists in the almost entire absence of 

 trees, and the scarcity even of shrubs except along the banks of the 

 principal rivers. Every one who has come from Rio de Janeiro to 

 Moute Video and Buenos Ayres has been struck by the contrast 

 between the gigantic vegetation of Brasil and the bare, treeless, 

 almost barren character of the shores of the Plata, where the culti- 

 vated Poplars, and the flower- stalks of the Agave, with here and 

 there a solitary Ombii tree (^Phytolacca dioica), are the only objects 

 that relieve the nakedness of the country. It is not that the vege- 

 table covering of the soil is really scanty ; but the vast majority of 

 the plants which compose it are herbaceous, of low growth, and for 

 the most part not very conspicuous. This treeless character has 

 been forcibly described, and its possible causes most ably discussed, 

 by Mr. Darwin in his ' Journal.' The immediate banks of the Uru- 

 guay and Parana, however, and the islands in those rivers, appear 

 to be wooded, although not with trees of great height or size. As 

 compared with Brasil, the vegetation of the Argentine region is 

 further distinguished (as might be expected) by the diminished num- 

 bers of tropical families, and also by something of a more European 

 physiognomy. Tlie resemblance in this particular appears, however, 

 to Mr. Bunbury to be not so great as has been represented, being in 

 a great measure due to the abundance of naturalized European 

 plants ; and excluding these, to consist rather in a certain general 

 similarity of character than in a real botanical analogy. Schouw's 

 estimate, that out of 109 genera which belong to Buenos Ayres, 

 70 appear in Europe, and St. Hilaire's statement, that of 500 spe- 

 cies collected by him in the Banda Oriental, only 15 belonged to 

 families completely strangers to Europe, are doubtless accurate so 

 far as they go ; but the vegetation of these countries is really more 

 different from the European than such comparisons would seem to 

 imply. For, in the first place, many families and genera, which are 

 strikingly characteristic of the Argentine region, are but scantily 

 represented in Europe. Such, in particular, are the families of So- 

 lanece, Verbenaceee, Amaranthacece, and perhaps Mulvacece. Of the 

 genus Solanum, for instance, many more species grow wild within a 

 short walk of Buenos Ayres than in the whole of Europe. The 

 genus Verbena, again, so insignificant in Europe, plays a conspicuous 

 part in the Argentine vegetation by the number of its species, the 

 profusion in which they grow, and their general brilliancy and 

 beauty. Secondly, although the genera altogether wanting in 

 Europe may not form numerically a very large proportion of the 

 Argentine Flora, yet several of them are very conspicuous, and play 

 an important part in that Flora by the number of species or of indi- 

 viduals : such are Pontederia, Gomphrena, Teleianthera, Jussitea, 

 Nicotiana, Petunia, Nierembergia, and others. Thirdly, several 

 families which most abound in Europe are nearly wanting, or but 

 very feebly represented (if we exclude naturalized plants) on the 

 shores of the Plata : such are CrucifertB, Curyophyllea, Umbellifer(E 

 (excepting Eryngium), Boragineee, Dipsacece, Cichoracea and Cy- 



