PRIMARY DIVISIONS. 103 



it seems at the same time probable from Bar(jii lIuiii])oldt'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 Dicotyleclones to Monocotjledoiies is at least that 

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

 somewhat diminished proportion of Dicotylcdones 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 iu possession, that the proportions 

 of the two primary divisions of phocnogamous plants vary 

 considerably even w^ithin 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, wdiich is also that 

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

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

 Island, and in the south of Europe. 



It is true indeed that from about 45° as far as to 6if, 

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

 diminution in the relative number of Dicotylcdones ; but it 

 by no means follows that in still higher latitudes a further 

 reduction of this primary division takes |)lace. On the 

 contrary, it seems probable from Chevalier 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- u^n 

 sions of phscnogamous plants are inverted on the more 

 northern parts of the coast ;^ Dicotylcdones being to 

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



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



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

 have been eonjectnred from a passage in Hans Egede's ' Dcscrijjtion of Green- 

 land,' where it is stated, that althongh from lat. GO'' to 05° 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, to keep their feet 

 warm, but are obliged to buy it from tiie southern parts." (Englisii Trans- 

 lation, pp. 11 and 17.) 



