Unseen Shades of Green

by A Meng and Tian Dong

On April 28， 2019， with the theme“Live Green， Live Better，” the International Horticultural Exhibition 2019 Beijing opened. During the expo， nearly 2，000 plants from all over the planet are on display， including 300 species of rare plants unique to China.

Plants create a welcoming home for mankind. In his book The Roots of Plant Intelligence， Italian botanist Stefano Mancuso asserted that of every 100 living things on the planet， 99.5 to 99.9 are plants， and that animals including humans account for only a tiny fraction of living organisms.

China has been the habitat for abundant plants since ancient times. It has continuous and complete tropical， subtropical， temperate and frigid vegetation， possessing all of the worlds major vegetation types except arctic tundra. A diverse and complex natural environment has made China home to 10 percent of the worlds total vegetation species， and the only home to many rare and endangered plants. A group of Chinese writers promoting science popularization have long been teaming up with nature photographers to spread concern for protection of Chinas rare and endangered plants. Over the past few years， they have researched， investigated and recorded a variety of plants in the wild including the critically endangered Paeonia ludlowii， Meconopsis adored by Western landscape architects， Urophysa rockii Ulbr which once was thought extinct， and endangered dove trees. They hope their efforts will raise awareness for protection of rare plants in China.

Surveys of Paeonia Ludlowii

Paeonia ludlowii， a species of peonies， is only found in Nyingchi Prefecture in southwestern Chinas Tibet Autonomous Region and abounds mostly in the prefectures Mainling County. Sometimes called the Tibetan tree peony， the plant is even more precious than the giant panda. The International Union for Conservation of Nature（IUCN） established a Red List of Threatened Species through which the extinction risk of thousands of species and subspecies were evaluated by a set of criteria. Species are classified by the IUCN Red List into nine groups with “extinct” and “extinct in the wild” at the top， followed by “critically endangered，” “endangered，” “vulnerable，” and “near threatened” in that order. In 2016， the giant panda was downgraded from“endangered” to “vulnerable” on the list while Paeonia ludlowii was classified as “critically endangered.”

However， this critically endangered species is still not on the official list of protected plants in China. Previously， the plant was believed to be the Delavays tree peony， a species widely found throughout provinces and autonomous regions such as Yunnan， Sichuan and Tibet. The differences in flower color and outline were considered normal variations. Although Paeonia ludlowii was eventually classified as an independent species by taxonomists， its name still hasnt reached Chinas official list of protected plants because the list hasnt upgraded for quite a while. During the years when the species wasnt properly protected， it was once exposed to risk of extinction. Local governments finally formulated protective measures such as fencing off key areas for the species to save it from trampling and consumption by livestock. The species gradually recovered.

In recent years， scientists have carried out wide-ranging ecological research on the species and its living environment， associated plants and differences from the Delavays tree peony in hopes of providing better protection. They eventually determined that the native species of China could be artificially cultivated into more ornamental varieties. Scientists will continue to carry out in-depth studies on its growth， reproduction， seed germination and seedling growth.

Searching for Meconopsis

Among Chinese plants， Meconopsis， a genus of flowering plants in the family Papaveraceae， is adored by many Western botanists. Several dozen species of the genus exist in the world among which most are found in the Himalayas.

Most Meconopsis species have blue flowers， but not all of them. The genus also includes some “mysterious” species. For example， Meconopsis pinnatifolia can only be found in Tibets Gyirong and Nyalam. Its flowers are purplish brown， and the plant is distributed only in a few areas that humans seldom visit. Meconopsis torquata is even rarer. The type specimen of this species was originally collected from hills in the suburbs of Lhasa. However， many experts at home and abroad have never seen the plant in the wild. According to locals， this plant was common in the past. However， those growing lower in the hills were long ago wiped out by medicinal herb pickers. All that is left today is only a small amount surviving in areas that are very difficult for humans to reach.

Without research and assessment， species like Meconopsis may never be enjoyed by people. The species that remain most unknown to the public are truly the most rare and endangered. They need more attention.

Rediscovery of Urophysa Rockii Ulbr

Although rare， it is exciting when a plant once considered extinct enjoys a renaissance.

In 1925， Austrian-American explorer and botanist Joseph F. Rock （1884-1962） took a plain plant specimen from Jiangyou City， Sichuan Province. After Rock returned to the United States， he confirmed that the plant was an unknown new species of Ranunculaceae and published an article on his findings. Learning of the news， Chinese botanists also ventured to Jiangyou for samples， but found nothing. The newly discovered species had disappeared quietly. The only information it left for humans was in two herbariums housed in the United States. Based on the two specimens， scientists determined it to be a unique Chinese genus “Urophysa，” a new species of Ranunculaceae. And this disappearing plant got an official name： Urophysa rockii Ulbr.

The beautiful plant is of high scientific value. When people looked deep into the development system of Ranunculaceae， they found the species to be an important key to the evolution of its genus. However， with only two specimens on hand， some evolutionary puzzles remained impossible to solve.

In 2005， after an absence of nearly 80 years， the plant was rediscovered in the newly built Wudu Reservoir in Jiangyou. The beautiful blue flowers enraptured people the moment they set eyes on them. After growing out of the stone walls of the reservoir foundation， the plant could have soon disappeared again without protection. So， the Wudu Reservoir postponed water storage. The local government and scientists spared no efforts to relocate the plants to be protected with hopes that the amazing species would once again thrive.

The Dove Tree Comes Home

Every year in April and May， the secluded Xiling Snow Mountain near Chengdu， Sichuan Province， becomes blanketed in spring green. It is the time when the flowers of dove trees bloom all over the mountain.

An endemic endangered species in China， dove trees are primarily distributed in alpine valleys around the Sichuan Basin. The climate in their habitat is warm and humid， with abundant rainfall. While rain benefits all plants， it also inconveniences the pollination process. Dove trees are free of this worry. They are tall and straight with flowers gathered on the top of the crown. Their white bracts resemble umbrellas， shielding the flower core from rain and preventing pollen released by staminate flowers to be soaked by water. When flowers are successfully pollinated， the bracts remain to protect the young fruits.

In April 1954 during the Geneva Conference in Switzerland， Chinese Premier Zhou Enlai witnessed the flowers of the dove tree in the courtyard. After learning that the tree was an endangered species native to China， he called for the reintroduction and protection of the species. The dove tree was officially included in the list of the first group of key wild plants under special state protection in China.

The dove tree was the cover image for the textbook Botany used by Chinese middle school students that was first published in 1982. Later， it appeared on the postage stamps issued by China Post. After 50 years of research and protection publicity， it has become a household plant in China.

Although the dove tree is a dominant species in its native land， it is still under first-class state protection today due to its poor fertility. The dove tree has benefited other species living within its habitat as an umbrella species.