296 J. A. MARTINDALE : NOTES ON BRITISH LICHENS. 



to give such a very meagre number of stations as, in this instance, is 

 recorded in his ' Lichen Flora.' So far, indeed, as this work is evidence, 

 we might suppose both plants to be very uncommon, for he only notes 

 two localities in England from which he had actually seen specimens 

 of C. rangiferina^ viz., in Yorkshire and Shropshire, and only one for 

 C. sylvatica, viz., Market Rasen in Lincolnshire. He records, indeed, 

 in another writing on the Cladoniei, published in the 'Annals and 

 Magazine of Natural History,' November 1866, the occurrence of 

 both species in Leicestershire, from whence he had received speci- 

 mens sent by Mr. Bloxam. 



This paucity of recorded stations may be taken as a proof how 

 completely the form sylvatica had been ignored by British botanists, 

 and rangiferina recorded wherever either plant was observed. Nor can 

 we supply our lack of information from any other trustworthy source. 

 Mr. Crombie, in his paper on the C7^7^^?;//>/ (Grevillea, vol. xi, p. 115), 

 enters into no details as to their distribution, merely 'saying of rangi- 

 ferina^ ' Probably general and common, but certainly less so than the 

 following species,' sylvatica^ of which he says, 'General and abundant. 



No one has pointed out with any emphasis that there are districts 

 in England where rangiferi?ta appears to be absent, but such I believe 

 to be the case. At any rate, I have not yet met with it in any part 

 of Westmorland that I have searched ; and as the Rev. W. Johnson 

 does not record it in his list of the Lichens of Cumberland, we may 

 suppose it to be absent from certain parts of that county also. 



And now to turn to another plant, Parmelia olivacea (L.), men- 

 tioned in the report above alluded to. It is a very prevalent opinion 

 that the large increase in the number of lichen species enumerated 

 in later British Floras over the earlier ones, is entirely due to the 

 making use for diagnostic purposes of minute differences of structure 

 revealed by the microscope, or from reactions obtained by the use of 

 chemicals. Now, though both these auxiharies have most properly 

 been made use of in the study of lichens, and a considerable number 

 of species have been more accurately limited by their means, which, 

 of course, has led to the recognition of species previously confounded 

 in some supposed polymorphous plant, yet the opinion above men- 

 tioned is only partially true, especially as regards the fohaceous and 

 fruticulose genera. The species now recognised which make up the 

 olivacea group of Parmelia are a very fair illustration of this. 



Eight species of the group are now known and recorded as 

 members of the British flora, along with a few varieties. But so far 

 from it being the case that their distinction from each other is due 

 either to the microscope or chemical tests, only two of them have 

 been named since 1830, and all of them had been described before 



Naturalist, 



