Rarest tree

The Wollemi pine (Wollemia nobilis), a member of the Araucaria family, was discovered in Wollemi National Park, 150 km (93 miles)north-west of Sydney, in 1994. Only 43 adult trees have been found, all growing in a 0.5-ha (1.5- acre) grove in the park in three small stands. The pine is particularly unusual in being covered with brown, knobbly, spongy bark. The trees grow on wet ledges in a deep, sheltered gorge. The tallest Wollemi pine known measures 40 m (131 ft) and has a girth of some 3 m (9 ft). The trees are direct descendants of a type of conifer that was common in the Cretaceous period (ending about 65 million years ago) but was thought to have been extinct for over 50 million years. The Wollemi pine is unusual in that it has no mechanism for shedding leaves individually: instead whole branches are shed, giving the forest floor a very distinctive character. The pine has also yielded the known anti-cancer chemical taxol.

In October 2005, the first generation of cultivated trees, up to six years old and 2.5 m (8 ft) high, were available for sale to the public at the Royal Botanic Gardens, Sydney, Australia, for £640 a specimen.