Linnaan Society. 465 



narea. In the collections in his possession from Buenos Ayres and 

 the Banda Oriental, Mr. Bunbury finds 14 families and 102 genera 

 which are not European. The families are Commelynaceee, Pontede- 

 racea, Bromeliacea, Marantacea, Calycerea, Bignoniacece, Passifloreee, 

 Loasece, Begoniacete, Buttneriaceee, Malpighiacece, Sapindacece, Tro- 

 peeolece and Melastomacece. The genera (adopting Endlicher'a 

 'Genera Plantarum' as the guide) are Paspalum, Stenotaphrum, 

 Cenchrus, Aristida, Chascolytrum, Pappophorum, Eustachys, Eleusine, 

 Androtrichum, Commelyna, Hydrocleis, Pontederia, Herreria, Udora, 

 Sisyrinchium, Cypella, Alstroemeria, Tillandsia, Oncidium, Canna, 

 Spathicarpa, Roubieva, Gomphrena, Teleianthera, Pupalia, Iresine, 

 Acicarpha, Boopis, Vernonia, Stevia, Baccharis, Pterocaulon, Haplo- 

 pappus, Flaveria, Porophyllum, Leighia, Verbesina, Achyrocline, 

 Trixis, Mitracarputn, Cephalanthus , Asclepias, Gomphocarpus, Oxy- 

 petalum, Arauja, Philibertia, Schistogyne, Lantana, Caloilyction, Ni- 

 cotiana, Nierembergia, Petunia, Jaborosa, Himeranthus, Oestrum, 

 Buddlea, Scoparia, Herpestes, Dicliptera, Bignonia, Argemone, Passi- 

 flora, Blumenbachia, Begonia ?, Pavonia, Sida, Abuttlon, Buttneria, 

 Stigmaphyllum, Heteropterys, Paullinia, Croton, Phyllanthus, Schinus, 

 Chymocarpus, Jussiaa, Heimia, Cuphea, Eugenia, Chcetogastra, Mi- 

 mosa, Desmanthus, Inga, Calliandra, Acacia, Parkinsonia, Cassia, 

 Poinciana P (perhaps introduced), Crotalaria, Indigofera, Tephrosia, 

 Daubentonia, Desmodium, jEschynomene, Clitoria, Camptosema, Cana- 

 valia, Galactia, Vigna, Erythrina ? (perhaps introduced), Rhynchosia, 

 Machtsrium. These lists are sufficient to show how materially the 

 Argentine Flora differs from that of Europe ; but what chiefly con- 

 tributes to give it at first sight a European character is the great 

 number and extraordinary prevalence of naturalized European plants, 

 which have spread so rapidly as to cover the soil to a great extent, 

 and actually to predominate over the native growth. The fallow 

 fields about Buenos Ayres are blue with Echium violaceum ; the 

 banks are covered with the common Fennel ; the ditch-sides and 

 waste grounds are overrun with Chenopodium album, Sonchus olera- 

 ceus and Xanthium spinosum ; T?-i/olium repens and Medicago denti- 

 culata form much of the herbage near the river-side ; and among 

 the most common grasses are Lolium perenne, L. multiflorum, Hor- 

 deum murinum and H. pratense. And these intrusive strangers are 

 not confined to the cultivated lands or to the neighbourhood of the 

 city; the "thistles" and "clover," which clothe the Pampas of 

 Buenos Ayres for leagues and leagues together, are Carduus Ma- 

 rianus, Cynara Cardunculus and Medicago denticulata, all of Euro- 

 pean origin. It is, as Mr. Darwin remarks, a parallel case to that 

 of the horse and ox, which have, within the last three centuries, 

 spread themselves in such countless numbers over the same 

 countries. Mr, Bunbury regards this wide diffusion of natu- 

 ralized plants as adverse to the views of those who consider the 

 natural distribution of species as determined solely by favourable 

 local circumstances ; the circumstances in the present instance 

 being evidently highly favourable to the plants in question, which 

 Ann.i^ Mag. N. Hist. Ser. 2. FW.xii. 32 



