196 MR. BUNBURY ON THE VEGETATION OF BUENOS AYRES 



savica, so common on the coasts of tropical Brazil, does not, apparently, extend much 

 hey on d the tropic. 



Umbelliferce. — These plants, observed by Humholdt to be very rare within the tropics, 

 unless at great heights, seem to be pretty numerous in the subtropical zone of the south- 

 ern hemisphere, but mostly of rather peculiar forms. The Umbelliferce of La Plata and 

 Rio Grande belong chiefly to the genus Eryngium, and especially to that curious section 

 of it with long, narrow, linear or sword-shaped, parallel-veined leaves (or phyllodia), which 

 are often fringed with bristles, or with bristle-like teeth. In Mr. Fox's collections from 

 those countries, I find nine species of Eryngium, of which five belong to the parallel- 

 veined section. One of them (E. aquaticum ?) is a stately plant, 5 or 6 feet high, a con- 

 spicuous ornament of the marsh ditches near Buenos Ayres, with leaves that remind one 

 of a Bromelia or Bandanus. Another (seemingly E. Pristis) extends from the tropical 

 regions of Brazil as far as 30° S. ; it is very frequent on the campos of Minas Geraes 

 (about 20°-21° S.), at the elevation of 2000 to 3000 feet, while in Rio Grande Mr. Fox 

 seems to have found it at a comparatively low level. Many Eryngiums of the same 

 group, and, as it appears, nearly allied to these South Brazilian kinds, were found by 

 Humboldt and Bonpland on the high lands of Mexico, and there are several in Chile. 



I find very few other Umbelliferce from the Argentine region in the collections before 

 me. This part of South America seems to be destitute of those curious Mulmece {Bolax, 

 &c.) which are so characteristic of Euegia, the Chilian Andes, and the Falkland Islands. 



At the Cape of Good Hope, in corresponding latitudes, we find very different forms of 

 this, as of most other families. That country has no Eryngiums, and I believe only a 

 solitary representative of that division of the order, the Alepidea ciliaris. It has, how- 

 ever, a considerable number of Umbelliferce, — not less than 120 species, according to 

 Harvey, — and among them several peculiar genera, of which Sermas and Arctopus are 

 the most singular ; likewise many remarkable forms of Hydrocotyle, which seem in a 

 manner to represent the South American Mulinece. 



Several European Umbelliferce have become naturalized at Buenos Ayres, and among 

 these the common Fennel is extremely conspicuous, covering the banks of earth between 

 the cultivated fields in immense profusion, and forming a distinctive feature in the scenery. 

 I have heard it remarked, by residents in that city, that when the wind called the Pam- 

 pero, which blows over the inland plains, is coming on, its approach is always announced 

 by the smell of Fennel, which it brings from the beds of this plant that it passes over. 

 Mr. Darwin observed the range of the Fennel to be limited on the south by the Rio Sa- 

 lado, rather less than 100 miles south of Buenos Ayres. 



Malpighiacece. — This is one of the characteristic tropical American orders which die out 

 rapidly in proceeding towards temperate latitudes. Two species only, as far as I know, 

 are found on the south side of the Plata, namely Stigmapliyllon littorale and Seteropterys 

 glabra. In Rio Grande, Mr. Fox collected nine Malpighiacece, of which one is a Galphi- 

 mia, the rest belong to Banisteria, Stigmaphyllon, and Seteropterys. 



Tropceolece. — Tropceolum (Chymocarpus) pentaphyllum, abundant in the hedges about 

 Buenos Ayres, seems to be the only plant of this order on the eastern side of temperate 

 South America. Its head-quarters are evidently on the western side of the continent. 



