FOKEIGN PLAl^'TS, HOW INTRODUCED. 65 



and, in fine, there are few vegetables of anj agricultural import- 

 ance, few ornamental trees or decorative plants, wMcli are not 

 now common to the three civilized continents. 



The statistics of vegetable emigration exhibit numerical results 

 quite surprising to those not familiar with the subject. The 

 lonely island of St. Helena is described as producing, at the time 

 of its discovery in the year 1501, about sixty vegetable species, 

 including some three or four known to grow elsewhere also.* At 

 the present time its flora numbers seven hundred and fifty species 

 — a natural result of the position of the island as the half-way 

 house on the great ocean highway between Europe and the East. 

 Humboldt and Bonpland found, among the unquestionably indig- 

 enous plants of tropical America, monocotyledons only, all the 

 dicotyledons of those extensive regions having been probably 

 introduced after the colonization of the ISTew "World by Spain.f 



The seven hundred new species which have found their way to 

 St. Helena within three centuries and a half, were certainly not 

 all, or even in the largest proportion, designedly planted there by 

 human art, and if we were well acquainted with vegetable emi- 

 gration, we should probably be able to show that man has inten- 1 

 tionally transferred fewer plants than he has accidentally intro- 

 duced into countries foreign to them. After the wheat, follow ' 

 the tares that infest it. The weeds that grow among the cereal 

 grains, the pests of the kitchen garden, are the same in America 

 as in Europe,:}: The overturning of a wagon, or any of the 



* It may be considered very highly probable, if not certain, that the undis- 

 criminating herbalists of the sixteenth century must have overlooked many 

 plants native to this island. An English botanist, in an hour's visit to Aden, 

 discovered several species of plants on rocks always reported, even by scien- 

 tific travellers, as absolutely barren. But after all, it appears to be well estab- 

 lished that the original flora of St. Helena was extremely limited, though now 

 counting hundreds of species. 



t See Wittwer, Physikalische Oeographie, Leipzig, 1855, pp. 486, 495. 



X Some years ago I made a collection of weeds in the wheat-fields of Upper 

 Egypt, and another in the gardens on the Bosphorus. Nearly all the plants 

 were identical with those which grow under the same conditions in New Eng- 

 land. I do not remember to have seen in America the scarlet wild poppy so 

 common in European grain-fields. I have heard, however, that it has lately 

 crossed the Atlantic, and I am not sorry for it. With our abundant harvests 

 of wheat, we can well afford to pay now and then a loaf of bread for the 

 cheerful radiance of this brilliant flower. 



