Of cultivated crops, wheat and barley are represented in the Pompeian frescoes, and grains of them have been discovered in the houses. In one pretty sketch a quail is picking at an ear of barley; in another at a kind of millet. Other less known cereals seem to have been familiar to the ancients. But two of the most important, both in an economic and picturesque point of view, are missing from these sketches,—maize and rice. Both are of modern introduction. The “polenta” of the classical peasant was of barley. Cotton, it need scarcely be added, is of very modern introduction; it now covers extensive fields at the southern foot of Vesuvius. After this long list of acquisitions, we must turn to some few instances of vegetable forms familiar to the ancient eye, and which the modern misses. The absolute extinction of a species is indeed a rare thing. Decandolle, in his ‘Geographie Botanique,’ likens the changes in vegetation to those which take place in a language: the appearance of a new word, or a new species, attracts observation at once; the disappearance of an old one is very gradual, and seldom total. We have already spoken of the comparative scarcity at present of deciduous trees, and of one—the æsculus—which modern botanists have been unable to define. But one or two ornamental foreigners, introduced in old times, have also disappeared, or nearly so. The most remarkable of these is the oriental Plane. Every Latin scholar is well aware of the modish passion for these trees which prevailed among the wealthy Romans, a preference not wholly æsthetic; it was partly a fashion, borrowed like other fashions from the despotic East, in days when republican millionaires at Rome, like those of Washington, had begun to discover that everything really meritorious came from lands possessing a “strong government.” The Platanus had been from hoary antiquity the object of veneration of Persian monarchs and Grecian heroes. No tree had anything like the same amount of historic and fabulous tradition attached to it. Marsyas was hanged on one, when duly skinned, by Apollo: Agamemnon and Menelaus planted a couple, each of which, a monstrous relic, was shown to Pausanias in his travels. Xerxes had caused his whole host to halt before a noble specimen in Lycia. “He was so enamoured of it,” says old Evelyn, “that for some days neither the concernment of his expedition, nor interest of honour, nor the necessary motion of his portentous army, could persuade him from it. He styled it his mistress, his minion, his goddess: and when he was forced to part from it, he caused a picture of it to be stamped on a model of gold, which he continually wore about him.” As it is now the glory of Ispahan and Shiraz, so it was of the Greek cities of yore. The groves of the Academe and Lyceum were composed of it. “By the Plane Tree” was the favourite oath of Socrates: the more shame to him, said his accuser Melitus, that he should blaspheme so fine a tree.