[MUSIC] The conifers are seed producing plants that protect their developing seeds within cones. The conifers are very succesful and although their present total number of species is relatively small, reaching about 600, they are of major ecological and economical importance. They particularly dominate the vast boreal forests of Siberia, Scandinavia, and Canada. The male cones produce pollen, and these are wind-pollinated. An example of conifer, considered to be a living fossil, is the Wollemia that you see here. Wollemia nobilis is the only living species within this genus, and it's as close as you can come to a living fossil. The oldest fossil of the Wollemias here, has been dated to around 80 million years. And Wollemia pollen are relatively abundant in Cretaceous deposits, showing that it was an important part of the Mesozoic ecosystems in the Southern Hemisphere. Based on the distribution of fossils, it was assumed that these plants progressively declined and died out about two million years ago. But, one day in 1994, so not so long ago, several strange looking trees were found, in a region in a national park just 150 kilometers northwest of Sydney in Australia. The natural population consists of just a handful of individuals clinging to life in a protected ravine. Since their discovery they have been cloned commercially, and the clones have been sold to botanical gardens and to private collectors worldwide. And here is one example and a really nice one. The Wollemia is a conifer within the family Araucariaceae, the monkey puzzle tree family. Wollemia novialis is the sole survivor of its genus. It's an evergreen tree reaching up to 40 meters in height and the bark is very distinctive, dark brown and bubbly. After a few years, some branches terminate in a cone and they have both female and male cones growing on the same trees. The seed cones, the female cones are green. And when they mature, they fall apart and drop their seeds. The more slender and reddish male cones all tend to grow on lower branches under the seed cones, thus avoiding self-pollination. The Wollemia however, also commonly has a growing habit called coppicing which means that the stem grows from the base of the original tree and each stem represents a clone. The leaves are flat and linear, and about three to eight centimeters long and about two to five millimeters broad. They are arranged spirally on the shoot, but twisted at the base. So, they look quite different to other conifers. The young leaves are first light green, by turn dark when they mature. Metasequoias, belonging to the redwood family, are another excellent example of a living fossil. They are large trees and they're well represented in the fossil record in the Cretaceous to Miocene deposits, so 100 to 20 million-year-old deposits. So Metasequoias were once thought to have become extinct during the Miocene. But in 1944, a population of previously unknown trees were found in Eastern China in the wetlands of the Hubei Province. Due to the war though, they were not described until 1948. And then identified as Metasequoia, the dawn redwood, and they were then classified as living fossils. There is only one living species in the genus, and that is Metasequoia glyptostroboides. It's the smallest of the redwood trees, but still it reaches at least 60 meters, so it's still a huge tree. Metasequoias are deciduous which means that they shed their leaves every autumn, which is actually an unusual habit within the conifers. The dawn redwood trees have leaves that are so-called oppositely arranged. And the individual leaves are about one to three centimeters long and bright green turning red-brown during the autumn. The pollen cones are small, at least reaching only one centimeter and they're produced in the spring. But can only grow in environments where the summers are really hot. The seed cones reach a size of 2 cm and these mature in nine months after pollination. This Metasequoia you see here is morphologically identical, meaning that it looks the same as the ancestor that lived 66 million years ago at the end of the Cretaceous. We have not talked about the real winners in the evolution of the land plants, the plant group that highly dominates with over 300,000 species, and which, without, we would not survive. Those are the flowering plants, the angiosperms. The first record of these is from early Cretaceous deposits, but their evolution was fast. And by the end of the Cretaceous they had out-competed most other plant groups. [MUSIC]