XI. CLEVIATAL ZONES. 489 



may be found in 



F'dices, 13 11 8 4 5 6. 

 But the rise here appears less regular, and becomes 

 slightly reversed again in the arctic zones. We should 

 requii'e to go down below no. 29 in the first column, to 

 find the starting place for 



Saxifragacece, 36 30 23 14 12 4. 

 This rise from the thirty-sixth to the fourth order shows 

 the decided tendency of saxifrages to prevail in the colder 

 climates. A rise in the like direction is much slighter in 



Caryophyllacece, 8 8 5 6 4 3. 

 Turning attention next to some of the orders charac- 

 terized by an opposite tendency, an example may be 

 cited in 



Orchidacea;, 11 13 14 16 17 0. 

 These sliowy monocotyledons may be contrasted against 

 the rushes ; though the changes in the reversed direction 

 are more gradual. No orchid has been ascertained 

 certainly above the midarctic zone. The same holds 

 true of 



Liliacece, 20 22 28 35 0, 

 which are absent also in the midarctic zone. But this 

 is partly a question of classification ; for the order would 

 he represented in both of the uppermost zones, according 

 to those systematists who place Narthecimn among the 

 lilies. Among dicotyledonous orders we may cite 



Leguminifer<e, 5 5 6 9 14 0, 

 as an example of decreasing numbers, and lower position 

 relatively to other orders, in the colder zones. And a 

 stronger example of the same tendency occurs in 



Umhelllfera;, 7 7 10 22 20 0. 



An irregularity occurs in the midarctic zone for that 



order, which may be again seen in the superarctic zone for 



Lamiacea, 9 99 18 28 16. 



VOL. IV. 3 B 



