86. GKAMINA. 179 



to be assigned, as it may pass under his eye ; and likewise, 

 to which species he must assign each and every single 

 station placed on record, whether under a right or under 

 a wrong name. To the degree or extent in which he fails 

 in this (often quite impossible) attempt, to the same de- 

 gree or extent will he be in danger of mis-describing the 

 distribution of allied and confused species. In the in- 

 stance here before us, the failure leaves the true upper 

 limit of Aii'a ceespitosa uncertain ; while not only are both 

 the upper and lower limits of Aii-a alpina left equally un- 

 certain, but its provincial area, comital census, noi-thern 

 and southern limits, must all partake of the like u.ncer- 

 tainty. This explanation may be deemed a divergence 

 from the onward course of the Cybele ; but this and other 

 divergences, introduced into so many of the notes sub- 

 joined to the regular formula here used for illustrating 

 distribution, are intended to convey suggestions to other 

 botanists, explanatory of botanical geography ; — explana- 

 tory of the objects to be attained, and the difficulties to be 

 overcome, in a department of botany as yet quite elemen- 

 tary and progressive ; and concerning which few of the 

 botanists of Britain can have yet had much experience, 

 or seem to have imbibed very clear and ample ideas. 



1302. AiRA FLEXUOSA, Liiiii. 



Area general. 



South limit in Cornwall, Isle of "Wight, Kent. 

 North limit in Shetland, Orkney, Hebrides. 

 Estimate of provinces 18. Estimate of counties 82. 

 Latitude 50 — 61. British type of distribution. 

 A. A. regions. Inferagrarian — Superai'ctic zones. 

 Descends to the coast level, in the Peninsula. 



