82 Watson's climatic zones. 



jniJla Good. Cave ne hue referas C. vesicariam alpigenam.'" How- 

 ever, in the vesicaria-huudle at Kew there is another sheet of 

 dichroa, issued in Andersson's Flora Lappotrlm Exsiccata (1865), on 

 which is written :" 272. Carexi^cesicaria) dichroa. Lapp. Lul. [here 

 follows a word which I could not decipher] . 1862. And." There 

 are three culms present, which have the fruit distinctly ribbed ; 

 they look intermediate between Grahami and alpigena, having a 

 moderately long beak and slightly scarious-tipped glumes. On this 

 evidence, I doubt whether dicliroa can really be separated from 

 alpigejia. It may be added that typical C. pulla, brought from Ben 

 Lawers in 1887, was grown in my garden at Witley for two years, 

 and did not alter appreciably. 



In conclusion, I must apologize for the length to which this 

 paper has run ; it seemed best not to omit any material particulars 

 which were at my disposal. 



WATSON'S CLIMATIC ZONES. 

 By Symers M. Macvicar. 



In Journ. Bot. 1894, p. 4, there is an article by Messrs. I. H. 

 Burkill and J. C. Willis, entitled '' Botanical Notes from North 

 Cardiganshire," in which altitudes are given of several species, 

 among these being Pteris with an average of 1270 ft. on the south 

 side of the hill. The authors mention that the average limit of this 

 plant on the south side of the Grampians, as given by Watson, is 

 1500 ft., and on this account come to the conclusion that the arctic 

 zone is nearer sea-level in Mid Wales than it is in the Highlands of 

 Scotland. This, I think, is an error against which Watson tells us 

 to be especially on our guard. 



Comparisons of altitudes of plants which ascend our hills for 

 some distance are apt to lead to false inferences, unless the hills 

 which are compared are of nearly equal height, and are under the 

 same conditions ; by this latter is meant principally whether the 

 hills arise from a table-land or long slope ; or are divided by glens 

 to nearly sea-level, as is so frequently the case on the west coast ; 

 and the presence or absence of such conditions should always be 

 stated. 



The highest point in the district of Nortli Cardiganshire is given 

 at 2460 ft., and that of the East Highlands, as given in Cyh. Brit., 

 at 4295 ft. ; and although it is mentioned that the higher the hills 

 are, the higher is the limit of the species, I think that the altitude 

 of 2460 ft. is so low that it comes under the conditions which 

 Watson gives as leading to an erroneous estimate when compared 

 with those of a hill about 4000 ft., when within a few degrees of 

 latitude. The authors also give Baber's heights for the Peak 

 District of Buxton (1750 ft.)— the Lake District (3206 ft.)— with 

 the extreme limit of Pteris at 1650 ft. in the former, and 1800 ft. in 

 the latter; also Watson's in the East Highlands at 1900 ft., and 



