336 THE JOURNAL OF BOTANY 



End, and Staunton, many more pits were opened. True, many of 

 these are now closed down, but the process of extension still goes 

 on, and with it more and more smoke and steam is poured out from 

 the chimneys of colliery workings and brick and pipe works, thus 

 daily making the atmosphere more highly charged with fine dust 



and carbon. 



To this must be added the smoke and dust, &c, arising from 

 the ever-increasing number of granite and other quarries or paving- 

 stone cement works that are being started, or are already in opera- 

 tion, in the neighbourhood. In this last instance, not only is the 

 atmosphere poisoned, but the rock itself, so essential to saxicolous 

 species of lichens, is being daily diminished in volume and extent, 

 and it is truly discouraging to the cryptogamic botanist to gaze on 

 the huge quarries at Bardon, where half this famous hill is being 

 blasted away by drilling and other operations, and this is also the 

 case further south at Croft and elsewhere. 



Thus, as a result of the extension of mining and other indus- 

 tries and the advance of civilization, the systematic botanist has 

 to face the gradual extinction of all lichens, and, sooner or later, 

 that of most hepatics and mosses, in those regions where at one 

 time they flourished best. This fact was first pointed out to me 

 by the Kev. H. P. Eeader, M.A., of Holy Cross Priory, Leicester 

 who has long studied and helped me to study the cryptogamic 

 plants of Central England. And not only in that region, but 

 indeed every where," as a result of the increased consumption of 

 coal and the diffusion of sulphurous gases which injure the leaves 

 of plants, it is becoming daily more patent that the atmosphere 

 of to-day will not nourish the plants that a century ago were from 

 other reasons losing their hold of their respective habitats owing 

 to draining or the extensive felling of woodland areas. This last 

 alteration brings in suitable conditions for other plants that have 

 a wider distribution, but now the increased amount of impurity in 

 the atmosphere causes these plants also to become gradually 

 scarcer and scarcer. 



This new feature in the struggle for existence amongst plants 

 has been dealt with purposely at some length, as it does not seem 

 to have been noticed by any other student of cryptogamic plants 

 in England, and as a committee for the consideration of the ex- 

 tinction of local plants exists, it seems a fitting occasion to draw 

 attention here to this new factor of destruction/' 



i 



* A paper was read last April, by Mr. P. Frazer, at the meeting of the 

 American Institute of Mining Engineers on the sources of injury to vegetation 

 in the neighbourhood of manufacturing works. 



t Since this paper was read Prof. Tansley has drawn the writer's attention to 

 a paper read at Bradford in 1900, by Mr. Albert Wilson, dealing with the effect of 

 smoke on vegetation generally in the North of England. In the abstract of his 

 paper Mr. Wilson mentions the effect of smoke on mosses and hepatics as com- 

 pared with that on higher plants :— " Smoke at a maximum in winter,, when many 

 mosses are in a vegetative condition. Great diminution in their abundance and 

 luxuriousness in the neighbourhood of large towns. Peculiar exposure of bark- 

 loving species io smoke influence, and the cause. Threatened extinction of 

 Ulota and Orthotricha." This bears out the foregoing statements as to the 



