The Living Collection at Quarryhill contains many rare and endangered species, a number of which are threatened with extinction in the wild. This categorization is due to habitat loss caused by human expansion and resultant deforestation, agricultural expansion, and resource consumption. The presence of these plants in the garden (as well as seed and herbarium specimens) helps to insure against total extinction, and provide a path for potential future re-introduction into endemic areas.
A small sample of some of the rarest of these include:
Rare and critically engangered in the wild, this unusual maple has been planted at Quarryhill in a number of locations. Botanists estimate that it will be extinct in China within a decade. As our first full-scale re-forestation project, we grew several hundred of these in pots, and have planted them in a forest of approximately two acres in the south-east expansion area of the garden. In several years, we expect to be able to produce diverse viable seed which can be sent to China to begin to effect re-forestation. Acer pentaphyllum is in essence the icon of Quarryhill, with its distinctive leaf in our logo.
Possibly the most threatened plant in the garden, this is one of only two in the US, and one of only about 50 remaining in the entire world. We have been attempting to propagate seed from the original expedition on which it was obtained, and have six successful plants growing in the nursery out of some 50 seeds. While unlikely that we would be able to obtain more seed in the wild, it is hoped that ultimately we can obtain viable seed from these plants and increase the stocks of this almost extinct tree.
Rare and endangered in China, this beautiful tree has a 'cousin', Liriodendron tulipifera, which is widespread and common in the eastern US. These two species make up the only two in its genus, and are an example of what is known as a disjunct species--they are very closely related, and were originally part of the same population before the continents separated millions of years ago.
Known as the dove tree, or the handkerchief tree for its large, white, drooping handkerchief-like bracts, this beautiful tree was discovered by, and named in honor of, the missionary and prolific French plant collector Père Armand David. Davidia involucrata was once widely distributed in China. However, its distribution area has shrunk greatly due primarily to exploitation and destruction of forest habitat. At present, it can be found scattered in evergreen or mixed evergreen and deciduous forests ranging from 600-2400 m in certain southwest China provinces.
Cephalotaxus fortunei var. alpina
Known by common names plum Yew or three-pointed fir, this species is rare in China, and listed as threatened in Vietnam by the World Conservation Monitoring Center. Sparsely distributed, it is endangered by both harvesting for timber and medicinal purposes throughout its range.
This magnolia is a very rare tree endemic to only a few places in Yunnan and adjacent Guangxi Province in southern China. It is one of five magnolias prioritized as "urgently in need of conservation action" by the Kunming Institute of Botany of the Chinese Academy of Sciences.
This pine comes closer than any other other pine to being deciduous. It displays a needle retention time of one year, the shortest of any pine. Pinus roxburghii is considered near-threatened and in need of conservation. Six mature specimens are happy in the Highland section of Quarryhill.
Endemic to central China, this plant is threatened by habitat loss, and under third-class protection under Chinese law.
According to the Red Data Book for China, this rose has become endangered as a wild plant by "picking and uprooting". This rose is widely planted at Quarryhill.
An important medicinal plant, this yew is protected under CITES (Convention on International Trade in Endangered Species) Appendix II, which lists species that are not necessarily threatened with extinction immediately, but may become so unless trade in specimens of those species is strictly regulated.