X. CLIMATE OF PLANTS. 471 



one step or no. Thus, Gramina and Cyperoides run in 

 nos. 2 and 3, Polygonacece in 15 and 16. One of the 

 widest differences among the 28 orders occurs in Saxifra- 

 gacecB ,- which rise from 29 (if the Kst had been carried 

 down to that no.) in the lowest stage, to 20 in the middle 

 stage, and to 9 in the uppermost stage. Some few of 

 these orders, however, are quite absent from the upper- 

 most stage, as Chenopodiace^ and Euphorbiace<e. 



In the eighth chapter ' altitude of species ' lists have 

 been printed for the purpose of showing the upper limits 

 of each species on the mountains of Scotland and North 

 England. If the absolute or the comparative heights 

 attained by individual species, should be required in more 

 exact detail than the indications given in the ' summary 

 of distribution ' under the three successive stages of alti- 

 tude, and under the six ascending or climatal zones, their 

 heights may be ascertained by reference to those lists. 

 And the vertical ranges of the plants, as affected by lati- 

 tude and other conditions, will still receive some further 

 incidental illustrations in the next section of these gene- 

 ral remarks on distribution. 



10. Relations of Plants tcith Climate. 



Incidental remai'ks, bearing upon the connexions be- 

 tween plants and climate, have been made in various 

 places throughout this volume, and occasionally in the 

 three preceding volumes. Indeed, it is scarcely possible 

 to treat about any of the geographical relations of plants, 

 without touching the all-pervading influence of climate 

 upon distribution. And yet, as was truly remarked on 

 page 145, " it is difficult even to present impossibility, to 

 trace out veiy special connexions between plants and cli- 

 mate" ; although, on the general view, the fact of very 



