We may here observe by the bye, that the _usnea cranii humani_, which thro’ the influence of superstition formerly obtained a place in the catalogues of the _materia medica_, does not belong to this division of the lichens. The writers of those times distinguished two kinds of _usnea humana_, under the names of _crustacea_ and _villosa_. Any of the crustaceous lichens, but more properly the common grey-blue pitted _lichenoides_ of Dillenius, was used for the former of these; and, as Dale tells us, was held in most esteem. The _villosa_ was a species of the genus of _hypnum_. Indeed it does not appear, that they were in those days very curious in determining the exact kind; and doubtless any moss, which happened to grow upon an human skull, was sufficient for the purposes designed. 2. Lichenes fruticulosi. _Such as consist of a tough flexible matter, formed into ramifications, in some species almost simple, in others resembling small shrubs: in some of the species the branches are quite solid, in others tubular._ This order comprehends the third of Dillenius’s genus of _coralloides_; the whole _cladonia_ of Hill; the second, and several species of the third order of Haller’s lichens; several species of the fifth, and the whole sixth, order of Micheli; and the _lichenes fruticulosi_ of Linnæus. The plants of this genus grow principally upon the ground on heaths, forests, and mountainous barren places; except the _orcelle_, or Canary-weed, which is found upon the rocks on the sea-coast. To this division belongs the horned moss[83]. It is found with us in rocky barren ground, and upon old walls not uncommon. It was formerly in great credit as a pectoral; but is now quite in disrepute.