58 BULLETIN [JNITED STATES GEOLOGICAL SURVEY. [Yol.vi. 



extra-tropical South America. On the Atlantic side there appears to 

 have beeD only a Blight commingling of warm-temperate United States 

 plants with the flora of the nearer tropical districts. Thus, the island 

 of Cuba has Pinus Elliottii (Cubenris), Tllidum parviflorum, some species 

 of Asimvna, all the NymphceacecB of the Atlantic flora, Ascyrum amplexi- 

 caule, &c.j our Ampelopsis and Yitis bipinnata, Ilex Dahoon, a Rhexia, 

 Oldenlandia glomerata, Houston id patens, Pterocaulon, Andromeda nitida, 

 CyrUUij Sabbatia gracilis, MitreolapeHolata, Laehnanthes tinctoria, Mayaca, 

 &c These, the Ampelopsis excopted, arc peculiar to the Atlantic coast. 

 ( 'aba, moreover, has a species of Kalmia ! 



But more speculative interest arises from the consideration of the 

 North American types, and in many cases the actual species, which re- 

 appear beyond the tropic in South America, on the western and not 

 rarely on the eastern side of that continent. There are a number of 

 plants indigenous to Chili, the presence of which in California — where 

 they are seemingly no less indigenous — maybe accounted for by the 

 immigration of men and cattle. This may have been the case with 

 Senebiera, Pentacama, Acama trifida, Plectritis (BetJiea) samolifoUa, Bow- 

 lesia lobata, Amblyopappus pusillus, Pectocarya, Lastarricea, and the like. 

 For Er odium cicutarium, Medicago denticulata, Melilotus parriflora, Oli- 

 gomeris subulata, and Arena fatua, which are now equally at home in 

 California, probably arrived by that route rather than direct from Eu- 

 rope. But we cannot in this way explain the presence in the two tem- 

 perate zones of plants such as the following, which we assume to be 

 North American species or types dispersed into South America. Some 

 few of them might with equal likelihood be viewed as Chilian types 

 with abnormal northern dispersion. We enumerate only such as come 

 to view without particular search, and exclusive of those which may 

 have been dispersed under man's unconscious agency. Identical species 

 in italics : 



Anemone decapetala. Trifolium microdon. 



Anemone multifida. Hosackia sabpinnata. 



Myosurus aristatus. Lathy rus maritimus. 



Sisymbrium canescens. Hoifmanseggia. 



Vcsicaria, said to be arctica. Prosopis (Algarobia) julifora. 



Malvastrum of North American Prosopis (Strombocarpa) sp. aft". 



type. Fragaria Chilensis. 



Splneralcea of North American type. Lepuropetalon spath ulatum (Atlantic 

 Modiola multifida (Atlantic). and Chilian). 



Sida (Pseudo-Malvastrum) sulphu- Gayophytum sp. 



rea. (Enothera sp. aff. 



Elatine Americano. (Enothera dentata. 



Larrca. (Enothera chciranthifolia. 



Rhus $ Lithraa, Boisduvalia sp. 



Lupinus )nierocarpus. Godetia sp. 



Trifolium MacraH. Mentzelia sp. aff. 



