IX. ALTITUDE. 409 



orders is so sliglit as to leave them increased relatively 

 to the much smaller total flora of the higher stage. This 

 is exemplified in the ' distributive census of orders' above 

 referred to, page 362, by the varying irregularity of the 

 numbers in the same column of figures. In the column 

 devoted to altitude, the first series of numbers is almost 

 regular ; that is, the orders which include the species 

 found below 200 yards follow nearly the same series as 

 the orders do for the whole of Britain. Here Scrophula- 

 riacece and Lamiacece simply change places; being 44 and 

 47 species, or nos. 10 and 9 of the series, instead of 

 9 and 10. Filices require to be placed two steps lower 

 down in the series ; sinking from no. 11 to no. 13. Jun- 

 cacece go down from no. 16 to no. 18. The few inequali- 

 ties left after these changes, would mostly depend on 

 single species in small orders. 



In the second series of the same column, under the 

 letter A, the numbers run more irregularly ; thus showing 

 that the numerical value of the orders, relatively to each 

 other, is so far changed in the second stage of altitude, 

 between 200 and 700 yards. In the third series of the 

 same column, under the letter U, the departure from re- 

 gularity is yet greater ; thus showing that the relative 

 numerical value of the orders, or their predominance in 

 species, differs much on the higher hills, when compared 

 with their relative value near the coast-level. 



Without repeating here the names of all the small 

 orders, which have been already given in detailed enume- 

 •ration in the distributive census list referred to, the sub- 

 joined re- arrangement will place in comparison the prin- 

 cipal orders of the three successive stages of altitude. 

 The names of the orders succeed each other in accordance 

 with the number of their included species, shown for each 

 of the three stages by the figures set after the names. 



