Old words in Natural History seldom become obsolete, but they change their meanings strangely. Were Dioscorides and Pliny _redivivi_, they would find nothing but misnomers! The term _Agaricus_, which anciently applied indiscriminately to all hard coriaceous funguses growing on trees (while the word _Fungus_ did imperfect duty for this genus), was next arbitrarily made by Linnæus to stand representative for such only as had gills, “fungi lamellati terrestres et _arborei_.”[115] Persoon, again, under the name _Amanita_ (a Galenic word, but hitherto unappropriated), made a new genus of such Agarics as were invaginated, _i. e._ shut up during the earlier period of their development in a volva; of such as had veins in place of gills, _Merulius_; and of such as had anastomosing gills formed another, _Dædalea_, a third division. More recently, Fries has greatly simplified the study of this very large and difficult genus by eliminating all of a coriaceous texture, and (having restored to it the genus _Amanita_) by then dividing the whole into sections; enabling us to arrive at an accuracy in the discrimination of species which was wholly unattainable before his time. His first grand series of Agarics comprehends those of white spores (LEUCOSPORI[116]), and of this his first section is— Subgenus 1. AMANITA.[117] All the Agarics belonging to this subgenus are, during the immaturity of the fungus, furnished with a volva and a ring; some have a velum in addition, and in this case, the surface of the pileus is covered with warts, or verrucæ. This natural division was adopted long ago by Micheli, who gave the name _Uovoli_ to those which had only the first two, and that of _Tignosi_ to those that had all three. Altogether they form but a very small group, but one very important to distinguish accurately, as it includes, besides one or two very delicate species, some which are highly poisonous. _Bot. Char._ _Pileus_ at first campanulate, then plane; fleshy towards the centre, attenuated at the margin; _gills_ ventricose, narrow behind, free, numerous, at length denticulate, the imperfect ones few, of a determinate form according to the kind, and, with one exception (that of _Ag. Cæsareus_), white. _Stalk_ generally enlarged at the base, frequently bulbous, solid, or stuffed with a cotton-like substance, which is at length absorbed; _ring_ descending, imperfect, fugacious; _flesh_ white, unchanging. Esculent species: _Ag. vaginatus_. Of the _Tignosi_, that is, those with warts on their surface, some have striated margins, others are without striæ. Esculent species: _Ag. rubescens_. Subgenus 2. LEPIOTA.[118]