1853.] Linnean Society. 229 



numerous at the Cape, are comparatively scarce, but the universal 

 genus Senecio abounds. Several of the CompositcG are tropical spe- 

 cies, and some (but these evidently naturalized) are common to both 

 hemispheres. 



AsclepiadetE are as numerous in Rio Grande and in the Argen- 

 tine region as in South America generally, although by no means 

 rivalling the Cape of Good Hope. Gomphocarpus fruticosus, gathered 

 at Monte Video, appears undistinguishable from the Cape plant, 

 but may have been accidentally introduced. With this exception, 

 and that of the genus Cynanchum, all the Asclepiadece belong to 

 strictly American forms, of which Oxypetalum predominates. 



Umbelliferce. — The plants of this family in La Plata and Rio 

 Grande chiefly belong to the genus Eryngium, and especially to the 

 section 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 are nine species, of which 

 five belong to this section. One of these (E. aquaticum ?) is a con- 

 spicuous ornament of the marsh-ditches near Buenos Ayres ; and 

 another (seemingly E. Pristis) extends from the tropical regions of 

 Brasil as far as 30° S. This part of South America seems to be 

 destitute of those curious Mulinece, which are so characteristic of 

 Fuegia, the Chilian Andes and the Falkland Islands ; but several 

 European Umbelliferce have become naturalized, and among them 

 the common Fennel, which covers the banks of earth between the 

 cultivated fields in immense profusion, and forms a distinctive feature 

 in the scenery. Mr. Darwin observed the range of the Fennel in 

 the south to be limited by the Rio Salado, rather less than 100 

 miles south of Buenos Ayres. 



Malpighiacea. — Only two species are found on the south side of 

 the Plata, viz. Stigmaphyllum littorale and Heteropterys glabra. In 

 Rio Grande, Mr. Fox collected nine Malpighiacea, of which one is 

 a Galphimia, and the rest belong to Banisieria, Stigmaphyllum and 

 Heteropterys. 



TropeeolecE. — The only plant of this family (the head-quarters of 

 which are evidently on the western side of the continent) found on 

 the eastern side of temperate South America is Tropceolum penta- 

 phyllum, abundant in the hedges about Buenos Ayres. 



CEnotheretK, Endl. — Some species of Jussicea are plentiful on the 

 marshy shores of the Plata, and Mr. Bunbury possesses three species 

 of (Enothera from Buenos Ayres ; but Epilobium and Fuchsia are 

 wanting in the Argentine region. 



Melastomacece. — One species only, as before mentioned, extends as 



