PRIMARY DIVISIONS. 103 



it seems at the same time probable from Baron Humboldt's 

 extensive collections, and from what we know of the vegeta- 

 tion of the West India islands, that in equinoctial America, 

 in tracts including a considerable portion of high land, the 

 ratio of Dicotyledones to Monocotyledones is at least that 

 of 11 to 2, or perhaps nearly 6 to 1. Whether this or a 

 somewhat diminished proportion of Dicotyledones exists 

 also in similar regions of other equinoctial countries, we 

 have not yet sufficient materials for determining. 



Upon the whole, however, it would seem from the facts 

 of which we are already in possession, that the proportions 

 of the two primary divisions of phBenogamous plants vary 

 considerably even within the tropics, from circumstances 

 connected certainly in some degree with temperature. But 

 there are facts also which render it probable, that these 

 proportions are not solely dependent on climate. Thus 

 the proportion of the Congo collection, which is also that 

 of the equinoctial part of New Holland, is found to exist 

 both in North and South Africa, as well as in Van Diemen's 

 Island, and in the south of Europe. 



It is true indeed that from about 45° as far as to 60°, 

 or perhaps even to 65° N. lat. there appears to be a gradual 

 diminution in the relative number of Dicotyledones ; but it 

 by no means follows that in still higher latitudes a further 

 reduction of this primary division takes place. On the 

 contrary, it seems probable from ChevaUer Giesecke's list of 

 the plants of the west coast of Greenland,^ on different 

 parts of which, from lat. 60° to 72°, he resided several 

 years, that the relative numbers of the two primary divi- l«i 

 sions of phsenogamous plants are inverted on the more 

 northern parts of the coast ;^ Dicotyledones being to 

 Monocotyledones, in the list referred to, as about 4 to 1, 



1 Article "Greenland," in Brewster's ' Edinburgh EncyclopBedia.' 



2 That some change of this kind takes place on that coast might perhaps 

 have been conjectured from a passage in Hans Egede's ' Description of Green- 

 land,' where it is stated, that although from lat. 60° to 65° there is a consider- 

 able proportion of good meadow land, yet in the more northern parts, the 

 inhabitants cannot gather grass enough to put in their shoes, t° kfJP '^■'; f;;f 

 warm, but are obliged to buy it from the southern parts. (Englibli Iians- 

 lation, pp. 4i and 47.) 



