'210 Transactions of the South African Philosophical Society. 



have a climate very similar to that of the Peninsula in its lower 

 portions, except that the rainfall is less, and the temperature is pro- 

 bably somewhat warmer. But there is little to lead us to suppose 

 that they present any serious barrier to the transmigration of living 

 organisms ; and, as a matter of fact, a large number of vegetable 

 forms in the Cape Peninsula are identical with, or closely allied to, 

 those in the region immediately beyond it ; in other words, the Cape 

 Flats forming the isthmus constitute, in no respect, a boundary 

 between two Floral Eegions. 



The South-western Kegion of the Cape Flora. 



A few words may conveniently here be said respecting the Floral 

 Hegion of which the Cape Peninsula forms the south-western extrem- 

 ity. This consists of an angular littoral strip, bounded on the west 

 coast by the Olifant's Eiver ; thence inland to the BokkeveldBerg, and 

 southward along considerable mountain chains under various names ; 

 thence eastward, generally more or less parallel with the coast, until 

 at last they trend towards the sea near the districts of Humansdorp 

 and Uitenhage. About this part the South-western Eegion gradually 

 passes into the Eastern or Sub-tropical Eegion, in the neighbour- 

 hood of the Van Stadensbergen, in the latter district."^' Its' greatest 

 width does not exceed eighty, and probably averages not more than 

 fifty miles ; while its length measured along the middle is about 500 

 miles. Its boundaries, since it passes over to other Eegions both on 

 its northern and eastern extremities, by a gradual transition, are 

 necessarily somewhat arbitrary and approximate. But inland, where 

 the mountains form an effectual check to the rain-bearing winds, 

 (whether from the westward or south-eastward) the boundary-line is 

 much more definite. 



Professor Ernst Meyer, of Koenigsberg, and J. F. Drege, the 

 botanical explorer and traveller (1826-34), were the first to investigate 

 South Africa from a phytogeographic point of view and to publish a 

 detailed scheme for its division into botanical Eegions and Sub- 

 Eegions.f These were based upon laborious recorded observations, 



* Kecent German writers have established a Transition Eegion (Uebergangs- 

 gebiet) between what I have called the South-western and Sub-tropical Kegions. 

 This appears to be scarcely an improvement on Drege's chief divisions. It 

 multiplies their number, which seems undesirable in view of the advantages of 

 clearness and simplicity ; it makes two somewhat arbitrary boundaries instead of 

 one ; and is open to the objection that the process of division might, with equal 

 reason, be carried on indefinitely. 



f Commentariorum de Flantis Africa Anstralioris, Leipsic, 1835 ; and Zivei 

 Pflanzen geograpJiische Dociimente, nehst einer Ehdeitung con Dr. E. Meyer, in the 

 ^' Flora" for 1843, vol. ii. 



