OX THE DISAPPEARANCE OF CRYPTOGAMIC PLANTS 337 



Not only in Leicestershire is this the case. In the Black 

 Country, where in former clays a good cryptogamic flora was to 

 be met with, scarcely a lichen is to be found, whilst the hepatics 

 and mosses have suffered to a similar extent from the same cause. 

 Even in the south of England, where factories are few and far 

 between, the same paucity is to be noticed. 



Thus it behoves the lichenologist particularly, and the student 

 of other groups of Cryptogam i a, to hasten to complete the syste- 

 matic study of the local floras still lingering on in the less popu- 

 lated districts of the British Islands ; for in years to come this 

 will be impossible. 



Lichens. 



The same agency which has caused the disappearance of so 

 many interesting and rare species of lichens in Leicestershire is 

 also responsible for another marked feature in the present lichen - 

 flora. It is found that numbers of specimens of the genera 

 Lecanora, Lecidea, and Verrucaria are imperfectly developed, 

 spores being absent, and the plants are frequently immature or 

 impoverished. It is thus often impossible to make a determination, 

 as distinctive characters are in these cases based largely on the 

 shape, size, and number of the spores ; and it is difficult in this 

 case to be sure whether a plant formerly recorded is not referable 

 to some one of these immature states, for though not still existing 

 in a perfect condition, it may be represented by examples of one 

 or other of these indeterminable specimens. This does not obtain, 

 however, largely except in the genera cited, which consist of 

 numerous species. 



The earliest record of a Leicestershire lichen is to be found in 

 Kay's Synoihsis, 1724, where Alcctoria jubata is mentioned on the 

 authority of Petiver as occurring in Charley Forest. This is 

 quoted by Withering in the 4th edition (1801) of his Systematic 

 Arrangement of British Plants from Dillenius (Hist. Muse. 1747). 

 Pulteney (1746), Crabbe (1795), Babington in Potter's Charnwood 

 Forest (1842), Coleman in White's Directory (1863), Brown in 

 Mosley's Natural History of Tutbury (1863), Leighton in his 

 Lichen Flora, 3rd edition (1879), Crombie (1895), and the author 

 (1904) have elaborated the catalogue of Leicestershire lichens. 



After collating the records contained in these lists, and sum- 

 marizing the results of recent work in the Charnwood Forest 

 region, it appears that none of the following plants, mainly con- 

 fined to that district, now exist there : — 



Collemodium biatorinum, Sphinctrina tremelloides, S. anglica, 

 Coniocybe fitrfuracea, Spluorophorus compressus, S. fragilis, S. 

 coralloides, Stereocaulon coralloides, S. denudation, Alectoria jubata, 

 Platysma sepincola, Podophyllum, Parmelia Mougeotii, P. incurva, 

 P. olivacea, Lobar ina scrobiculata, Stictina sylvatica, Lobaria 



nature of the effects of increased smoke, and also extends to the North of 

 England the area here indicated as particularly affected by its agency. Prof. 

 Tansley informed the author that in the neighbourhood of Huddersfield this 

 year he noticed that lichens were almost conspicuous by their absence. 



