Editor's note: From the deep sea to the mountains, from deserts to rainforests, plant imprints are found everywhere on earth. A world of changing years, climate change, geological movement, habitat change, plants that have endured and remain diverse in evolution. Voice of the Chinese Academy of Sciences and the Wuhan Botanical Garden of the Chinese Academy of Sciences jointly opened "Flowers and Flowers of All Things", where we pay attention to the survival, competition, reproduction and death of plants, display the strange and colorful nature of the natural world, interpret the thousands of meteorological phenomena of life, explore the magical secret of life, and pay tribute to this silent and vigorous world.
In the pre-Qin period, the Classic of Mountains and Seas and the Southern Classic of the Great Wilderness recorded: "In the great wilderness, there is the mountain of Tu Zhi (xiǔ), and the green water is poor. There are mountains of clouds and rain, there are wood names such as Luan, Yu attacking cloud rain, there are red stone Yansheng Luan, yellow ben, red branches, green leaves, and the emperor of the group to take medicine. "It is said that there is a mountain of Tutu and a mountain of clouds and rain in the great wilderness. There is a tree on Yunyu Mountain called Luan Tree, which grows on red stone, with yellow trunks, red branches, and blue leaves. This is the earliest ancient record of Luan trees in China. As a native tree species in China, Luan trees have long been discovered and planted by the ancients. According to the Northern Song Dynasty Shen Kuo's "Mengxi Pen Talk", as early as the Han Dynasty, the ancients planted luan trees in the courtyard.
On National Day, the day when the Chinese people celebrate with the whole world, the Luan tree is full of red fruits, like bells, swaying branches, like a spring blooming flowers, celebrating the motherland with lights, and is truly called "National Day Flower".
The flowers of Luan tree branches (Photo: Zhang Lijun)
Luan tree is a collective name for plants of the genus Luan in the subfamily Apocynaceae. It is a deciduous tree, native to most provinces and regions of China, from Liaoning to the southwest of Yunnan and Taiwan, China, and now it is cultivated all over the world. Its flower and fruit characteristics are very obvious, and the recognition is very high.
The flowers are dioecious but identical to the inflorescence, and the large, expanded inflorescence is clustered and conical, usually apically at the top of the twigs, with a very large number of branches on each inflorescence, and several small branches regenerate on each branch. The flowers grow on these small branches, small but large, and can have hundreds or thousands of flowers on each inflorescence. Although the single flower is small, the structure of the male and female flowers is very different. Both male and female flowers have 4 linear oblong yellow petals, when flowering, they are folded outwards, interestingly, the base of the petals has two raised ridges, the front looks like the capital letter "M", the initial bloom of the flower, the folded ridge is tender yellow, as the flower is fully open, it gradually becomes bright red, and a little red in the yellow-green bush is particularly eye-catching. When the male flowers first bloom, the petals are evenly arranged in the shape of a lotus seat, and with the stamens fully protruding, the 4 petals gradually deflect to one side and the stamens to the other. The pistils of the female flowers are thick and slender, slightly curved, and protrude long above the petals, shaped like the beak of the very New Zealand national bird "kiwi".
Luan Shu Xionghua (Source: China Plant Image Library)
Female flower of Luan tree (Source: Chinese Plant Image Library)
The flowering period of the luan trees lasts for more than three months, from the beginning of June to the middle of September, and when they bloom, a faint fragrance fills the air. The breeze blows, as if there is a "flower rain", and the small flowers are broken and fall to the ground, and the mood is particularly elegant.
The Flower of Luan Tree (Photo: Zhang Lijun)
Flowers dropped by Luan trees (Image from the Internet)
The luan tree is an "acute seed", and the flowers can't wait to bear fruit after withering, and some inflorescences even bear fruit while flowering. The fruit of the tree is like a flower and not a leaf, like a small lantern hanging from the branches, gradually changing colors, beautiful. Therefore, the luan tree is also known as the lantern tree.
Luan tree flowers and fruits with the same branch (picture from the network)
The fruit of the luan tree is a bunch of clusters of capsules. The fruit is surrounded by three petals, has three ridges, and when ripe, usually has 3-6 spherical black seeds inside. The petals are papery, thin, with a reticulated outer surface and a smooth and slightly glossy inside. The fruit is light green at the beginning of its growth, turns red when ripe, and turns brown when dry.
In early autumn, you can often see a tall luan tree, green leaves, yellow inflorescences, red fruits, in the sunlight, glittering. In late autumn, the ripe and dry fruits rustle when the breeze blows, and the sound of copper coins is the same as in ancient times, so the luan tree is also called "cash cow". In addition, the practical value of Luan tree seeds is also very high, and its seeds contain oil, can be pressed, can be made of lubricating oil and soap, and are excellent woody oil plants.
Luan tree seeds (Source: China Plant Image Library)
There are 4 species and 1 variant of Luan trees, except for 1 species produced in Fiji, the rest are all produced in China, namely Luan tree (Koelreuteria paniculata Laxm.), Taiwan luan tree (Koelreuteria elegans subsp. formosana (Hayata) Meyer), Koelreuteria bipinnata Franch.), full-leaf luan tree (Koelreuteria bipinnatavar. integrifoliola), of which the Taiwan Luan tree is a unique tree species in Taiwan, the main feature is that the leaves are large, the second odd or even pinnate compound leaves, there are 5 petals, golden and apex pointed, in Hainan, Fujian, Xiamen and other places have introduced species, good growth. The seeds of the Taiwan luan tree are round and hard, which can be made into Buddha rosary beads, also known as "wooden luan seeds".
The luan tree with upright tree shape and beautiful seasonal appearance is very popular in landscaping and is an excellent greening tree species. Its spring leaves, late summer and early autumn flowers, late autumn and early winter leaves and fruit, late winter can also explore the bark. The young leaves in spring are red and green, fresh and pleasant; the golden inflorescence in autumn and summer is dazzling; the red leaves that change color are brilliant; the fruits in autumn and winter are like small red lanterns hanging from the branches, beautiful and infinite; in the deep winter, the bark stomata is very obvious. It can be used as a shade tree and a street tree, planted by the creek, pool, garden road or lawn edge. At the same time, luan trees can not only absorb heavy metals, but also have strong resistance to toxic gases such as sulfur dioxide and chlorine, and can also adsorb soot. It is suitable as an ecological tree species and is planted in areas such as factory mining areas as pollution shelterbelts.
Luan Tree Street Tree (Image from the Internet)
Luan tree plant (Photo: Zhang Lijun)
In addition to the appearance of the line, the leaves of the Luan tree as "wild game" are also fresh and delicious. The first stage of young leaf buds that grow in spring, commonly known as "wood buds" or "magnolia buds" in folklore, can be eaten as vegetables. After soaking to remove the bitter taste, it is cold or made into the filling, the taste is light and delicious, and the nutrition is rich. Young leaves are edible, and the role of mature leaves cannot be underestimated. The leaves of luan tree contain tannin, which can be used to make glue; the leaf juice has a strong antibacterial effect; and it can also dye silk in the yellow system.
Young leaf buds of Luan tree (Source: China Plant Image Library)
In ancient China, where the hierarchy was strict, trees were also the same as people, and their status was high and low. The luan tree with such a beautiful appearance was called "Doctor Tree" in ancient times, and its social status was not low. In the Zhou Li, it is recorded: "Tianzi Shu Pine, Princes Bai, Dafu Luan, Shi Huai, Shu ren Yang". The rules are the tree species planted next to the mausoleum after the death of people of all classes. The emperor is equipped with pine trees, the princes and nobles are equipped with cypress trees, and the scholars are equipped with luan trees. The so-called "punishment can not be a doctor" shows that the official position of a scholar is an important position and his status is not low. As a native tree species in China, Luan Tree is not only an ancient and famous tree, which has witnessed the changes of the vicissitudes of the mulberry field, but also become an important member of the historical archives of Chinese civilization.
The low-key and shy flowers of the luan tree bloom modestly on the branches, and may be missed if they are not careful, but the fruits are bright red throughout the autumn, showing the joy of harvest and ripening. "On the day of the candle, the single valerian shines." Before frost leaves, can increase the autumn spectrum. It is the description of the luan tree in the "Botanical Names and Facts", and the grass and wood books praise and praise its wonderful scenery with poetic and beautiful words. When the whole world celebrates, take advantage of the autumn light to feel the beauty of the Luan tree.
Inflorescence of Luan tree branches (Photo: Zhang Lijun)
bibliography:
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3. WU Liang,FU Jiajia. Research progress on germplasm resources of Luan trees[J].Hebei Agricultural Machinery 2016(6):24-25.
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Source: Wuhan Botanical Garden, Chinese Academy of Sciences