196 MR. BUNBURY ON THE VEGETATION OF BUENOS AYRES 
savica, so common on the coasts of tropical Brazil, does not, apparently, extend much 
beyond the tropic. | : 
Umbellifere.—These plants, observed by Humboldt 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 Umbellifere 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 Pandanus. Another (seemingly E. Pristis) extends from the tropical 
regions of Brazil as far as 30° 8.; it is very frequent on the campos of Minas Geraes 
(about 207-21? 8.), 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 Umbellifere from the Argentine region in the collections before 
me. This part of South America seems to be destitute of those curious Mulinee (Bolax, 
&e.) which are so characteristic of Fuegia, 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 Umbellifere,—not less than 120 species, according to 
Harvey,—and among them several peculiar genera, of which Hermas and Arctopus are 
the most singular; likewise many remarkable forms of Hydrocotyle, which seem in a 
manner to represent the South American Mulinee. 
Several European Umbellifere 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. - 
Malpighiaceæ.—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 Stigmaphyllon littorale and Heteropterys 
glabra. In Rio Grande, Mr. Fox collected nine Malpighiacee, of which one is a Galphi- 
mia, the rest belong to Banisteria, Stigmaphyllon, and Heteropterys. 
Tropeolee.— Tropeolum (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. 
