Metasequoia glyptostroboides

Metasequoia glyptostroboides, the dawn redwood, is a fast-growing, endangered deciduous conifer, the sole living species of the genus Metasequoia, one of three species in the subfamily Sequoioideae. It now survives only in wet lower slopes and montane river and stream valleys in the border region of Hubei and Hunan provinces and Chongqing municipality in south-central China, notably in Lichuan county in Hubei. Although shortest of the redwoods, it can grow to at least 165 ft (50 m) in height. In 1941, the genus Metasequoia was originally reported by palaeobotanist Shigeru Miki as a widely distributed extinct genus based on fossils, before attracting considerable attention a few years later when small populations were found alive in central China. It is a particularly well-known example of a living fossil species. The tree faces considerable risks of extinction in its wild range due to deforestation, and so has been planted extensively in arboreta worldwide, where it has proved a popular and fast-growing ornamental plant. Though once common across the northern hemisphere, the dawn redwood was originally considered extinct. The genus Metasequoia was first described in 1941 as a fossil of the Mesozoic Era, and none of the fossils discovered was less than 150 million years old. Dr. Shigeru Miki (1901–1974), a paleobotanist from Kyoto University, identified a divergent leaf form while studying fossil samples of the family Cupressaceae and realized he was looking at a new genus, which he named Metasequoia, meaning 'like a sequoia'. In the same year a forester named T. Kan came across an enormous living specimen while performing a survey in Sichuan and Hubei provinces. Though unaware of Miki's new genus, he recognized the unique traits of the tree. It formed part of a local shrine, where villagers called it Shui-shan 水杉 or 'water fir'. In 1943, Zhan Wang (1911–2000), a Chinese forestry official, collected samples from an unidentified tree in the village of Maodaoqi or Modaoxi (presently, Moudao) in Lichuan County, Hubei province—now believed to be the same tree Kan discovered. The samples were determined to belong to a tree yet unknown to science, but World War II postponed further study. Professors Wan Chun Cheng and Hu Xiansu made the pivotal connection between Miki's genus and the living samples in 1946, and provided the specific epithet 'glyptostroboides', after its resemblance to the Chinese swamp cypress (Glyptostrobus). In 1948 the Arnold Arboretum of Harvard University funded an expedition to collect seeds from Kan's original tree and, soon after, distributed seeds and seedlings to various universities and arboreta worldwide for growth trials. Of these, two were distributed to the H. H. Hunnewell estate in Wellesley, Massachusetts, where they were still alive as of 2016. The seeds distributed to Hillier Gardens near Winchester, UK, have thrived and are now the emblem of the gardens. Seedlings have been for sale since 1949. The first Dawn Redwood to be planted out in the UK was at the Cambridge University Botanic Garden. The seed was not from the Arnold expedition, but somehow came to Cambridge directly. The Botanic Garden’s Annual Report for 1949 declares: ‘Seeds of Metasequoia glyptostroboides, sent by Dr Silow from China to Professor F T Brooks, germinated freely. Three of the seedlings have been planted out: one in the Yard at the back of the Range and two beside the Pond .' The tree on the south-west side of the Lake is still living, as at July 2019.