which are sent me to be named, beginners are very apt to fall. Practice will also in time enable the tyro to use the hammer and chisel in such a way as to obtain neat specimens of saxicole species--a matter of importance with respect to their subsequent mounting. As to the best season for collecting, I need scarcely remind the reader that lichens are perennial plants, remarkable for their longevity, and that during the whole year round they may be found in fruit. The lichenist has not to wait for any particular month or months, as other botanists have to do, before he can collect the objects of his search in a fully-developed condition. Spring, summer, autumn, and even winter, except when the snow conceals all vegetation beneath its white mantle, are all alike to him, and in each he will find every species of lichen in perfection. At the same time, he will be most successful after a shower of rain or a slight frost has fallen, inasmuch as, becoming swollen with the moisture then imbibed, many of the minuter species which might otherwise be overlooked, are more readily perceived, and the foliaceous species more easily removed from the substratum to which they are more or less closely affixed. Nothing more need be said on the collecting of lichens, as a short experience will be more useful than further details. We proceed, therefore, to give a few hints on their subsequent preservation. This is a very easy process, presenting no difficulty whatever, and occupying but little time. We shall suppose that the collector has returned from a successful expedition, with his vasculum or haversack well filled with specimens from all sorts of habitats. Opening the papers in which they have been wrapped up, he will take them out one by one, and place them separately upon a table, over which a newspaper has previously been spread. If gathered in wet weather, they ought not to be left long in the papers, as in this case they are very apt to become covered with mould. After allowing them to remain in this position till they are thoroughly dry, he may at once proceed with hammer and chisel, or with knife and scissors, to reduce to a suitable size such of them as he could not conveniently thus manipulate in the field. When this is done, they may then be affixed with gum, of a rather thick consistency, to slips of white paper, with the locality and date of their collection written beneath. There will be no difficulty felt in thus affixing saxicole, corticole, and lignicole species, though where the nature of the stone or wood is more absorbent, several applications of the gum may be necessary before they properly adhere. With terricole species, however, a somewhat more lengthened process is necessary, owing to the brittle nature of the substratum, in consequence of which, if not properly preserved, they often crumble into dust in the herbarium. To prevent this, M. Norman, of Trömsoe, Norway, has recently prescribed a