THE whole class of mosses were taken but very little notice of by the revivers of botany in the sixteenth century: they indeed took some pains to distinguish the particular species that the ancients had mentioned, but disregarded almost all the rest. Modern botanists however suppose, that they were but little successful in general in their application of the ancient names to plants: nor is a failure in such attempts to be wondered at, considering the too great conciseness, and frequent obscurity, of their descriptions. In the class of mosses, as in many others, the accounts transmitted to us are little more than a scene of uncertainty and confusion. It is to the moderns we are indebted for the discovery of the far greater number of the plants of this class. In this branch of botany our own countrymen Mr. Ray, Buddle, Dale, Doody, Petiver, and Dr. Morison, Sherard, Richardson, and others, have distinguished themselves: and amongst foreigners M. Vaillant, Sig. Micheli, and the very eminent Dr. Haller: but, beyond all, the late learned and indefatigable professor at Oxford, Dr. Dillenius, has herein made the most ample discoveries and improvements, of which his elaborate history will ever remain a standing proof. The word _lichen_ occurs in the writings of Dioscorides and Pliny; and tho’ it may be doubtful, there is nevertheless good reason to apprehend, that Dioscorides meant to describe under that name the very plant, or at least one of the same genus, to which the commentators agreed to affix his description. Since then the name has been variously applied by different authors; on which account it is necessary to premise, that the _lichen sive hepatica Off._ or liverwort of the shops, does not fall under this generical term, as it is now formed by the three above-named authors. They comprehend under the term _Lichen_, and Dillenius under those of _Usnea_, _Coralloides_, and _Lichenoides_, the hairy tree-moss or _usnea_ of the shops; the _muscus pulmonarius_, tree-lungwort, or oak-lungs; the _lichen terrestris cinereus_, or ash-coloured ground liverwort; the coralline-mosses; the cup-mosses; horned mosses; the _orchel_, or Canary-weed; the _muscus islandicus_ of Bartholine; and a multitude of others found upon trees, walls, rocks, and stones, in all parts of the world, and in many parts thereof in very great abundance. Caspar Bauhine in his _Pinax_, John Bauhine, and countrymen Gerard and Parkinson, and their cotemporaries, as they wrote before the time that generical characters in botany were in use, included these lichens among the other herbaceous mosses, under the general name of _muscus_; adding to the name in general some epithet descriptive of its form, place of growth, or supposed virtue.