122.The first public botanic garden established in Europe appears to have been that of Pisa, which was begun, according to Deleuze, in 1544, by Cosmo de' Medici; and Ghini and Cï¾µsalpini, celebrated botanists, were successively its directors. Belon, a French naturalist, who was at Pisa in 1555, was astonished at the beauty of the garden, the quantity of plants it contained, and the care taken to make them prosper. In the beginning of the eighteenth century, a great accession was obtained to the garden by the double flowers of Holland, then introduced into Italy for the first time. (Calvio, Hist. Pisani.) The garden of Florence was established in 1544 (Targioni, Prod. Chorograph. Toscan.); that of Bologna, under Pope Pius V., by Lucas Ghinus, the first professor of botany in Europe, in 1547, or, according to some, in 1568; and that of Rome soon afterwards. From that time to the present day, the numbers of botanic gardens have been continually increasing, so that there is now one belonging to almost every principal city in Italy; an exertion the more remarkable, as botanic gardens in that country are proportionably more expensive than in England, from the necessity of conveying a stream of water to them, and forming a regular system of irrigation.