276 NOTES ON THE ECOLOGY OF LICHENS, WITH SPECIAL REFERENCE TO EPPING FOREST. By R. Paulson. F.L.S. With Five Illustrations, [Read 23rd January 1918.] AFTER three years and a half of a most disastrous war, which has brought in its train a great shortage of food, everybody realises the national importance of an exact knowledge of the relation of plant to soil and environment. Questions respecting the reclaiming of saltings, the breaking up of pasture-land by the plough, and the re-afforestation of large tracts are all claiming solution. Ecology, one of the newest branches of biological science, has something to offer in the way of guidance as the result of various experimental methods that were being worked out in times of peace. I am aware that my subject touches upon the fringe only of that of Forestry ; but that of the Ecology of Fungi, with which it is so closely related, is of the utmost importance. It is only with a fuller knowledge of the several groups of crypto- gams that we can come to a more exact understanding of the various plant-associations of the Forest. Turning for a moment from the purely-utilitarian aspect of what has just been said, we could wish to add the words moss, lichen, and fungus after the plants enumerated in the following paragraph by E. N. Buxton1:— " The peculiarities of the various woods which I have endeavoured to indicate are not confined to the larger growths, but extend to that which covers the surface grass, heather, brake-fern, gorse, broom, or black-thom, according to the soil and aspect. From the above remarks, it will be seen what a charming diversity we have inherited—incomparably more interesting than a wood which, however beautiful, is all of one pattern." Five years have elapsed since the second and concluding part of the "Report on the Lichens of Epping Forest," by Paulson and Thompson, was placed before the Essex Field Club2. In that report, a small section was given to habitats and plant- associations as they exist in the Forest area. Since then, I have occupied some of my spare time in comparing the lichen- flora of the Forest with that of other woods and heaths in counties 1 Epping Forest, 5.157(1905). 2 Essex Naturalist, xvii, pp. 90-105 (1914).