GENERAL REMARKS ON DISTRIBUTION OF 



PLANTS. 



When we study the history of a country, we ought to he acquainted 

 with its geography, its physiognomy of the landscape, its climate and 

 the physical qualities of its people. All these things will influence the 

 moral character of the people and only in that way, combining cause and 

 effect, we will gain a clear view of its history. 



Likewise when we study the flora of a country, it is not sufficient to 

 know the names and characteristic qualities of all the species that grow in 

 a certain district; we ought to know the circumstances under which they 

 grow, the topography, the climate, the nature of the soil aud the geo- 

 graphical distribution of each species beyond the limits of the country in 

 question. 



This branch of science, known by the name of phytogeography, is a 

 comparatively new one; it was founded in the first decennium of our cen- 

 tury by Alexander Humboldt, when he published, in 1805, his " Essai sur 

 la Geographic des Plantes," and in 1817, his " Prolegomena de Distribu- 

 tione Geographica Plantarum." 



Since that time many botanists, by treatises on single countries or on 

 single groups of plants, have furnished material to more general works on 

 the subject, f. i., Wahlenberg on the flora of Lapponia, 1812; on the 

 vegetation and climate of Northern Switzerland, 1813; in his Flora Gar- 

 pathorum, 1814. Robt. Brown, in his " General Remarks, Geographical 

 and Systematical on the Botany of Terra Australis, 1814, etc. 



The first attempt to arrange the vegetation of our globe into separate 

 geographical divisions was made by the Danish botanist Schouw, in 1822, 

 when he published " Grundtrack til en almindelig Plantegeographie," 

 followed in 1824 by an Atlas of twenty-two maps. He used the names of 

 the characteristic orders for each of his divisions: For North America, 

 three only; the most northern, from 50 N. L. northward, he called the 

 Kingdom of Saxifrageae and Mosses; the Northern United States and 

 Canada formed that of the Asters and Solidagines; the Southern States 

 that of the Magnolias. The country between the Rocky Mountains and 

 the Pacific Coast, the flora of which was at that time nearl}^ unknown, he 

 passed by. Meyen, the botanist of the Prussian expedition around the 

 world in 1830-32, published in 1836 a general work on the Geography of 

 Plants. The most important works on the subject are the " Geographic 

 Botanique," by Alph. De CandoUe (1855), and " Grisebach's Vegetation 

 of the Earth," in 1872. 



