Sedum sedum is released! Is Sedum a succulent plant?

Recently, the internationally renowned journal Plant Taxonomy published an article about the discovery of a new species by researchers from the Forestry and Grassland Bureau of Jiangshan City, Zhejiang Province. The article named the new species they discovered during a field survey in Jianglang Mountain Scenic Area as "Sedum sedum" . This species has become the youngest member of the Sedum genus family in the Rosaceae family of the dicotyledonous plant class.

The newly named Sedum serrata (Photo source: Jiangshan Publishing House)

The genus Sedum has more than 1,500 members and is a major player in the succulent plant family. As a typical ornamental plant, Sedum is loved by people for its drought tolerance, good growth, excellent medicinal properties, and long history .

The first choice for succulent family viewing

Succulent plants refer to plants that use one or more of their roots, stems, and leaves to store large amounts of water, and appear thick and fleshy in appearance. They are also called succulent plants, or "succulent" for short.

Succulents are representatives of drought-tolerant plants, with beautiful appearance, cute looks, easy to grow and hardy. They mainly live in the cracks between rocks on hillsides, on rocky slopes under forests, and on the cliffs of deep valleys. They happily accept the gift of sunlight and are very easy to manage and maintain as long as the temperature is maintained between 15℃ and 18℃.

The succulent family is very large, with more than 10,000 species in the world, mainly distributed in America, Africa and other places. Common ones include cactus, aloe, oleander, etc. The most famous family is the Crassulaceae, which includes more than 1,500 varieties of 34 genera such as Sedum, Babao, Echeveria, Kalanchoe, etc.

Echeveria succulent

As the leader of the Crassulaceae family, the genus Sedum has about 600 species, which are distributed in temperate and tropical alpine areas around the world, showing tenacious vitality. They grow upright, with short and compact plants, and their leaves are mostly fleshy and delicate, giving people a unique touch.

The flowers are small but dense, and the flowering period is long, combining the beauty of leaves, stems and flowers into one, making them an ideal choice for park greening, home gardening or rock garden layout.

Sedums are notable for their unique biological characteristics . First, they are short and drought-tolerant and have excellent pollution tolerance, which makes them ideal for green roofs.

Secondly, they have a unique way of photosynthesis . At night, when the temperature drops, the leaves open their stomata, quietly absorb carbon dioxide, and temporarily store it in the cells in a special form; when the temperature rises during the day, the leaves close their stomata to prevent water loss, and the previously stored carbon dioxide is released again as one of the raw materials for photosynthesis to produce the nutrients needed by the plant. This ingenious mechanism allows Sedum plants to obtain carbon dioxide while avoiding water loss , demonstrating their excellent ability to adapt to the environment.

The poetic name of the best medicine

In addition to being ornamental, Sedum plants also have strong medicinal value . This was discovered by the Chinese working people more than 2,000 years ago. The famous medical book "Shennong's Herbal Classic" produced in the Han Dynasty listed the bitter and sour Sedum as a top-grade medicine, saying that it has the effects of clearing away heat and detoxifying, promoting blood circulation and stopping bleeding.

The origin of the name "Jingtian" is quite poetic. It was originally used to describe the flickering light of fireflies. Zhang Yi of the Eastern Han Dynasty wrote in his book "Guangya": "Jingtian means firefly." Cui Bao of the Jin Dynasty further described it in "Ancient and Modern Notes on Fish and Insects": "Firefly is also called Yaoye and Jingtian." This is because when fireflies fly at night, the dots of light they emit are very similar to the flowers of the Crassulaceae plants viewed from a distance, both of which are dotted and dazzling, so people gave this plant the beautiful name "Jingtian".

In "Wu Pu's Materia Medica" written by Wu Pu of the Three Kingdoms (a student of the famous doctor Hua Tuo), multiple names of "Sedum" were mentioned: "One name for firefly is Yezhao, one is Yiyao, one is Jiuhuo, one is Jingtian, one is Juhuo, and one is Jiahuo." These names not only show the rich connotation of "Sedum", but also reflect the ancients' delicate observation and poetic expression of natural phenomena.

To this day, Sedum has different names in different regions of China: people in the north call it variegated Sedum, people in the south call it Hawksbill Sedum, and in Shanghai it is called Edo Purple (actually it refers to the plant of the genus Kalanchoe in the Crassulaceae family).

Kalanchoe and Brugmansia

Historically, Sedum was confused with another plant called "Babao" for a long time. In the Tang Dynasty, people called the eight imperial seals used by the emperor "Babao", while in the Song and Ming dynasties, this name referred to eight or more precious treasures. In the early Qing Dynasty, people in the capital began to use "Babao" to refer to a plant similar to Sedum. This change may be related to the multiple uses of Sedum, which has multiple functions such as avoiding fire, removing fire, clearing heat, detoxifying, promoting blood circulation, stopping bleeding, removing blood stasis, and ornamental .

In the next few hundred years, "Babao" became the official name in the industry, and "Sedum" gradually became an alias. It was not until after the liberation that Chinese scientists reorganized the two and classified them both into the Crassulaceae family, but in different genera.

The difference between Sedum and Sedum plants mainly manifests itself in two aspects.

Firstly, from the perspective of flower shape , the bases of the carpels of Sedum flowers are connected together, like "hand in hand", while the bases of the carpels of Sedum flowers are completely separate and not connected to each other. This feature is recorded in detail in the "Flora of China".

Furthermore, from the perspective of growth habits , Sedum plants mainly grow in subtropical and tropical arid areas, and most of them can only withstand low temperatures of around -5°C. They can remain evergreen in all seasons and will not shed leaves. Babao plants belong to the perennial root category and show extraordinary cold resistance. They can withstand severe cold as low as -20°C or even lower. Therefore, they are widely distributed in temperate to cold regions. Their above-ground parts may die in winter and sprout again in spring.

The significance of Sedum serrata

In the vast family of Sedum plants, despite its rich variety, the discovery of new species is extremely rare . However, Sedum serrata has become a shining star in this field.

In March 2022, researchers from Jiangshan City, Zhejiang Province, accidentally discovered this unique plant species while climbing a mountain. Subsequently, they worked together with experts from the Zhejiang Museum of Natural History and, after two years of rigorous morphological and molecular biological analysis, finally confirmed that Sedum serrata is a new member of the Crassulaceae family.

This classification is based on two pieces of evidence. First, its appearance is strikingly similar to that of the Taiwania sedum of the Crassulaceae family . Its slender, solitary stems and flat leaves give it unique ornamental value. Second, the growth environment of Sedum sedum is similar to that of most Crassulaceae plants . It takes root in the mosses of rock walls and grows tenaciously despite the harsh environment.

It is worth mentioning that the discovery of Sedum scoparia is the first time that botanists have discovered a new species in the area after Jianglang Mountain was listed as a World Natural Heritage Site.

This discovery not only enriches the knowledge of the botanical community, but also rings the alarm bell for us to protect the environment. Let us work together to protect these precious natural resources and look forward to discovering more new plant species in the future.

References:

"Study on Biological Characteristics and Cultivation Techniques of Crassulaceae Succulent Plants", author Li Jingmin, "Journal of Shanghai Jiaotong University (2017)"

"Study on the adaptability of 15 succulent plants of Crassulaceae to open-field cultivation", author Lu Jie, "Green Technology" April 2019

"Study on Sedum", author Guo Jinli, Li Guopeng, etc., "Anhui Agricultural Science" 2014 No. 17

Author: Wei Deyong, member of Shenzhen Writers Association, Guangdong

Editor: Dong Xiaoxian