The word _Boletus_, which now stands for a large genus of the section _Pileati_, was used in ancient Rome to designate that particular mushroom which had the honour, under Agrippina’s orders and Locusta’s cookery, of poisoning Claudius; in memory of which event it is now called _Amanita Cæsarea_, the Cæsar’s mushroom. It occurs frequently both in the poets and prose writers of those days, and was in high esteem, as we collect from Pliny, who, though no mushroom-fancier himself, calls this “Boletus optimi cibi.” Nero, in playful allusion to his uncle’s death, of which it was the occasion, designates it the ‘food of gods,’ βρῶμα θεῶν; and Martial celebrates it in many a convivial epigram; in one, for instance, where he asks his hard-hearted patron, “what possible pleasure it can be for his guests to sit at his table, and see him devour boletuses;” in another, “gold and silver and dresses may be trusted to a messenger, but not a boletus, (_subaudi_) because he will eat it on the way.” This is the only ancient mushroom which we at once recognize by the description of it; “it originates,” says Pliny, “in a volva, or purse, in which it lies at first concealed as in an egg; breaking through this, it rises upwards on its stalk; the colour of its cap is red; it takes a week to pass through the various stages of its growth and declension.” The _suillus_—probably the same as the modern _porcino_ (a word of analogous import), which was, and is, eaten by men as well as pigs, and not always by these[7]—was, according to Pliny, the fungus which most readily lent itself to poisoning by mistake; a remark so far consonant to modern experience, that it is liable, without some attention, to be confounded with the _Boletus luridus_, _B. cyanescens_, and others, which in their general shape and external hue resemble it, though it is not by any means certain that any of these species, with which it may be confounded, are themselves poisonous.[8] The word _tuber_, though it occasionally (as in Juvenal) meant the _truffle_, seems to have been used with considerable latitude. Thus the _tubers_ said to spring up after those _optatos imbres_, those “long-wished-for showers of spring,” were, probably, not truffles, but puff-balls, which, at the season of warm rains grow with incredible rapidity, forming an esteemed article of luxury, not only in Italy, but also in India; whereas the truffle never makes its appearance in the markets at such times, nor comes up so immediately after rain. _Tuber_, like our ancient “_fusseball_,” seems a common appellation both for truffles and puff-balls. What the ancients understood by _hydnum_ is as little precise or discriminate as the last word; for Theophrastus declares it to have a light bark, λειόφλοιον εἶναι, in which case it is a puff-ball, while the plant called ὑδνοφίλον, which is said to indicate the whereabouts of _hydna_ in its neighbourhood, can only refer to the truffle.