438 APPENDIX Or. 



the whole number of phanerogamous species included in the 

 Flora of the region, and opposite the name of each natural order 

 I have entered the number of species found in each region, and 

 the percentage proportion which this number bears to the en- 

 tire flora. Besides the orders which bear the largest proportion 

 in the Great Atlas Flora I have enumerated those that usually 

 characterise the vegetation of high mountains in this part of 

 the world, though several of these are little, or not at all, repre- 

 sented in the Flora of the Great Atlas. 



Confining the comparison in the first instance to the figures 

 given for the Atlas Flora as a whole in the first cokimn, and those 

 given in the fourth, sixth, seventh, and eighth columns respect- 

 ively, for the Sierra Nevada, the Bulgardagh, Dalmatia, and 

 the southern side of the Alps, we remark in the first place that 

 Monocotyledons bear about the same proportion to Dicotyledons 

 in the Great Atlas that they do in the Sierra Nevada, the per- 

 centage here being much larger than it is in the Bulgardagh, and 

 considerably less than in Dalmatia or the Southern Alps. In 

 this part of the world this percentage in the Flora of a given 

 region mainly depends upon the number of Oraminece and 

 Gyperacem. The abundance of the latter groiip in the Alps 

 doubtless arises from the fact that at a former period physical 

 conditions favoured the migration of a large number of 

 northern species that have been unable to extend to the more 

 southern mountain regions of the Mediterranean area. 



In all the regions iinder consideration we find, with a single 

 exception, that the same eight natural orders take precedence 

 of all others as regards the number of species that they exhibit, 

 the aggregate in every case exceeding one-half of the whole 

 phanerogamous Flora. These natural orders are Conipositoe, 

 Leguminosm, Graminem, Oaryophyllece, Cruoiferce, Labiates, 

 Scrophularinece, and Umhelliferce. The exception arises from 

 the prevalence, already noticed, of Gyperacem in the Flora of 

 the Southern Alps. In comparing the figures in the Great 

 Atlas column with those for the other areas above enumerated, 

 it is well to recollect that our materials are taken from a 

 district much more limited in extent than the others, and are 

 necessarily imperfect, because obtained from a single short visit 

 to each valley at a .season when many species are yet unde- 

 veloped. It is probable, for instance, that the proportion of 



