XII. TYPES OF DISTRIBUTIOX. 513 



On looking to the tabultir arrangement, tlie numbers 

 will appear to run very unevenly or irregularly. As here- 

 tofore, the names of the orders are placed in a series 

 according with their predominance in the total flora. 

 The columns of figures for the tj^pes, indicated by their 

 initial letters, succeed one another in accordance with 

 the total number of species assigned to them respectively. 

 Hence, if the numbers were evenly apportioned, they 

 ought to show a constant decrease downward in each 

 column, and a like decrease along each line read from left 

 to right, from B to I. This is far from being the case ; 

 and doubtless there is some reason or explanation to be 

 found for each of the various irregularities. Some of the 

 explanations are artificial ; that is, they originate in arbi- 

 trary interpretations of nature put forth in books. Others 

 are natural ; that is, they arise out of climatal and other 

 physical conditions, independently of human caprice. 



Rosacete afford an example of the former. This order 

 has the largest figure under the English type ; the expla- 

 nation of which is found in the excessive subdivision of 

 the genus Riihus, and the present necessity for assigning 

 the ill-ascertained distribution of so many of its alleged 

 species either to the English or to the Local type. So 

 again, excessive subdivision of the genus Hieracium into 

 ill-defined species, with ill-understood distribution, un- 

 duly raises the figure for Compositce under the Highland 

 type. Thus it comes, repeated over and over again, that 

 an excessive subdivision of the species under a few genera, 

 on a different principle from that followed in regard to 

 the species of other genera, introduces anomalies and 

 confusion into other departments of botanical science, 

 besides the descriptive. Injudicious dabbling with spe- 

 cies is not simply a harmless process, but one calculated 

 to do much mischief, through falsifying the data required 



VOL. IV. 3 u 



