24 MEETING OF THE BRITISH ASSOCIATION. 
which originated at the British Association meeting of 1838, at New- 
castle, and which circum navigated the globe, visiting many oceanic 
islets, making magnetical observations in these, and prosecuting geo- 
graphical discovery in high southern latitudes. 
In illustration of this subject, Dr. Hooker exhibited Colonel Sir H. 
James's ten-foot projection of two-thirds of the sphere on a plane, 
which gave, in their approximately true positions, the islets he chose 
as illustrations of his subject, and the continents to which their floras 
were related. These islands were Madeira, the Canaries, Azores, and 
St. Helena, in the Atlantic, and Kerguelen's Land, in the South In- 
dian Ocean. 
The Madman flora he described as being composed of two ele- 
ments, tbe one clearly allied to that of the shores of the Mediterranean, 
the other totally different, and allied to none other but what was 
found in the Canaries and Azores, and which he designated " The 
Atlantic Element." The European (Mediterranean) element he clas- 
sified into groups of plants which showed a graduated passage from 
those identical with Mediterranean species to those very different 
generically, but still always allied to Mediterranean plants,— the steps 
being— 1. Identical species ; 2. Varieties (obscurely marked and well 
marked) ; 3. Distinct species of Mediterranean genera, which were 
subdivided into obscurely-marked species (ranked by some as varieties), 
well-marked representative species, and very distinct species; and 
4. Distinct genera, which may be grouped into similar subdivisions. 
He next proceeded to show that there was a certain amount of 
parallelism between the commonest of the plants composing the Me- 
diterranean element and those most divergent from the Mediterranean 
flora, the species identical with Mediterranean plants being much 
more numerous and abundant, the distinct genera being fewest and 
most rare in individuals. 
In comparing the Madeira group, viz. Madeira, Porto Santo, and the 
Dezertas, the floras of the several islets were next shown to differ ma- 
terially from one another, in varieties, species, and even genera, much 
in the same way as the flora of the whole group differed from the Me- 
diterranean. 
The Madeira mountains contain no alpine plants, and few represen- 
tatives of the plants of higher northern latitudes. 
Comparing Madeira with Great Britain, or any continental area of 
