The Montezuma Cypress

Nothing else in Florence comes from Mexico, has a trunk seven metres around, and survived being struck by lightning barely a decade ago. This Montezuma cypress, a cousin of the American bald cypress native to riverbanks around Mexico City, went into the ground at the Giardino dei Semplici in the 1880s, brought north as one of the many botanical trophies nineteenth century gardens competed to acquire. It grew for over a century without much incident, reaching a girth few trees on this list can match, before a September 2014 storm hit it directly, splitting and reshaping its crown in a single afternoon. The tree survived, though its silhouette now carries the asymmetry of that strike rather than the tidy pyramid shape the species usually holds. In its native range this cypress can live for a thousand years or more, most famously as the Arbol del Tule near Oaxaca, one of the stoutest trees on Earth; Florence's specimen is a comparative youngster, but it is already the widest girthed tree in this entire list. Visitors touring the botanical garden for its more famous residents, the Medici era yew and the cork oak nearby, often walk straight past it without registering that they have just passed something that does not grow naturally anywhere within four thousand kilometres of Tuscany.