These common flowers are best trampled to death when you see them

In recent years, Canada goldenrod has suddenly become known to many people, and it often appears on various media platforms as a "devil" invasive plant .

Official media accounts have also published articles many times to educate the public about the disadvantages of invasive species | WeChat public account @People's Daily

Biological invasion is not just about the spread of alien species to local areas. They also occupy the living resources of native species, causing economic or ecological losses . In 2009, a news report on the official website of the United Nations showed that invasive species can cause economic losses of up to $1.4 trillion worldwide each year.

In order to prevent and control invasive species, we must first know what invasive species they are. There are 71 invasive alien species listed in the "List of Alien Invasive Species in China", including 40 plants, 6 vertebrates, and 25 invertebrates. We have listed the 10 most common plants, let's identify them together:

Canada goldenrod

Some of the invasive alien species were introduced into China because they look good, such as Solidago canadensis. This is a plant of the genus Solidago in the Asteraceae family. As its name suggests, the flowers are clusters of yellow flower heads growing on the top of the stem. There are about 120 species in this genus, almost all of which are distributed in the Americas. There are 6 species in China, 3 of which are introduced.

Canada goldenrod that invaded Japan｜Akiyoshi Matsuoka/Wikimedia Commons

How to distinguish Canada solidago from other species of the same genus that can be seen in China? The most intuitive difference lies in the direction of the inflorescence : the inflorescence heads of Canada solidago grow in the same direction on the inflorescence axis, while the inflorescence heads of other species grow in all directions; the same-side growth also causes the inflorescence of Canada solidago to often bend .

The picture above is Canada solidago, whose inflorescence only grows upwards; the picture below is the native solidago (S. virgaurea), whose inflorescence faces all directions｜David Stang / ZipcodeZoo.com; Sten Porse / Wikimedia Commons

Canada goldenrod has a strong ability to spread. It has long rhizomes that can extend underground; the fruit has pappus that can be spread by the wind, or carried away by water or animals. The fruit yield is also not small. A normal plant can produce about 20,000-50,000 seeds in a year, and the natural germination rate of seeds can reach 30% . Studies have shown that most of the Canada goldenrod that has invaded China are hexaploid , while most of them are diploid in its place of origin. The difference in ploidy also enhances the invasive ability of domestic individuals.

During its growth process, this plant will also secrete allelopathic substances into the soil, inhibiting the germination and growth of other plants and improving the soil to make it more suitable for itself.

Water hyacinth

Water hyacinth (Eichhornia crassipes) was introduced to China to meet the needs of foodies - however, the foodies here are not humans, but farmed animals. Water hyacinth was originally used as feed , but after a while people found that animals were not very interested in these foods, so they abandoned them and did not centrally process them. Over time, these "feeds" spread in the waters of southern China through their own efforts and eventually occupied a place.

Water hyacinth blooms, and the enlarged petioles can be seen in the picture｜Eugene Zelenko / Wikimedia Commons

Water hyacinth, also known as water hyacinth and water hyacinth, belongs to the genus Water hyacinth of the family Pleurotus. This genus has about 7 species, which are found in tropical regions of Africa and America. Water hyacinth is native to Brazil and is the only species of this genus that has entered China. Although the Flora of China lists multiple uses for water hyacinth such as feed, vegetables, medicinal and environmental monitoring, it still cannot change its nature as an invasive organism - on the water surface without artificial control, a water hyacinth plant can quickly become a sea of ​​water hyacinths, and after a while there will only be water hyacinths .

The petiole of water hyacinth is swollen like a gourd, and it grows in water, hence the name "water hyacinth". The swollen part contains rich aeration tissue, which allows it to float on the water surface; the spread of water hyacinth can cover the entire water surface, preventing sunlight from reaching the water, thus affecting the ecological environment of the water body.

Occupy the water surface, and the other creatures underwater will suffer｜Hans Hillewaert / Wikimedia Commons

Damn weeds

Some invasive species are brought in accidentally by humans, such as Lolium temulentum, which entered China mixed with imported grains .

But it is more difficult to identify species in the Poaceae family than in the Asteraceae family! ｜H. Zell / Wikimedia Commons

The reason why tares are called tares is because they have a certain degree of toxicity. This toxicity is not produced by the tares themselves, but the tares are often infected by specific fungi and produce taresin , which is a toxin that is anesthetic and toxic to humans and animals and may cause poisoning in humans and animals.

In addition to being easily toxic, poisonous weeds are also very resilient. Once seeds fall into farmland, poisonous weeds will grow in the fields, competing with crops for nutrients and ultimately causing a reduction in yield . Newly fallen seeds can also easily mix into harvested grains, further spreading the toxicity . Therefore, poisonous weeds not only affect the ecological environment, but can also directly affect our lives.

Poisonous wheat | H. Zell / Wikimedia Commons

Lantana

Lantana camara is native to America, but now it is often seen in southern China . Lantana camara blooms beautifully, with the small flowers on the head opening from the outside to the inside, and the color of the small flowers gradually changes from light yellow to darker, so there are often small flowers of multiple colors on one inflorescence. Lantana camara is therefore called "five-color plum".

Lantana is beautiful, but it grows in the wrong place and has become an invasive species｜Samratmaina2019 / Wikimedia Commons

Lantana has another common name - stinky flower, also called stinky grass. This is because the leaves of Lantana contain terpenoids, which are compounds with strange smells that prevent them from being eaten , so they have almost no natural enemies.

Lantana fruit turns black when ripe｜そらみみ/Wikimedia Commons

Lantana not only has no natural enemies, but is also very adaptable and can survive well in many types of soil. In addition, it has a high fruiting rate and, like Canada goldenrod, can release chemicals that inhibit the growth of other plants. Lantana can easily invade the land and destroy the growth of native species and the local ecological environment.

In addition to the "stinky grass" Lantana, the false stinkweed Praxelis clematidea is also an invasive species in my country｜Alex Popovkin / Wikimedia Commons

Mikania micrantha

Mikania micrantha is native to Central and South America. It was introduced to Southeast Asia in the mid-20th century and is now a common invasive plant in the south. Mikania micrantha is a climbing plant of the Asteraceae family. Its flowers are beautiful, like small white flowers decorating a green waterfall - but this is exactly what makes them scary.

A cascading green waterfall | Mikania micrantha / Wikimedia Commons

Mikania has a very good climbing ability. In the south, it is often seen entwined around large trees, which prevents the affected plants from getting sunlight . The small white flowers are the capitula of Mikania, which is a typical feature of Asteraceae plants. The capitula contains many small flowers. Although the inflorescence of Mikania is not large, there are many of them . The seeds produced are covered with pappus like dandelions and are blown away by the wind.

Mikania can also reproduce asexually , and after the branches are broken, it can grow adventitious roots to continue to settle down, and it is not afraid of being trampled to death. In addition, Mikania can also release allelopathic substances into the soil, affecting the growth of other plants .

A close-up look at the flower head of Mikania micrantha | Mikania micrantha / Wikimedia Commons

Eupatorium adenophorum

Ageratina adenophora, also a member of the Asteraceae family, is native to Mexico and was first introduced to Europe as an ornamental plant and then spread to all parts of the world. In Yunnan, the spread area of ​​Ageratina adenophora has reached 64%.

Eupatorium adenophorum｜Forest and Kim Starr / Wikimedia Commons

Purple loosestrife also has the "double insurance" of sexual reproduction and asexual reproduction - its seeds also have pappus, which can be blown away by the wind; the developed creeping rhizomes allow it to spread on the ground. In addition, the roots of purple loosestrife can also secrete chemicals that hinder the growth of other plants.

The stems are purple, a characteristic of Eupatorium adenophorum｜Forest and Kim Starr / Wikimedia Commons

Ragweed

Ragweed (Ambrosia artemisiifolia) is also from the Asteraceae family! Ragweed is native to America, but has now invaded all over the world. In my country, ragweed can be found from the northeast to the south of the Yangtze River.

Ragweed |Dendrofil / Wikimedia Commons

Ragweed is very resilient . With its well-developed root system and above-ground parts, it can compete for nutrients and water below and sunlight above, which not only damages the ecology but also causes a reduction in agricultural production. The head inflorescence of ragweed is divided into male and female. The male inflorescence will produce a small number of sterile flowers, but this still cannot change the strong reproductive capacity of ragweed, with each plant producing 70,000 to 100,000 seeds per year.

The trouble caused by ragweed is not only a biological invasion, the yellow mist-like pollen it produces is also the main allergen for autumn pollen allergy .

The same genus, ragweed, is also an invasive species and a significant allergen | sbs.utexas.edu

Bidens pilosa

Bidens pilosa...how come it's in the Asteraceae family? Bidens pilosa is native to America, but now it can be found in Eurasia, Africa, Australia and other places.

Bidens pilosa｜Juan Carlos Fonseca Mata / Wikimedia Commons

Bidens pilosa has a typical head inflorescence of the Asteraceae family. Many people may have seen the yellow and white color combination of the variant white Bidens pilosa on the roadside. In addition, Bidens pilosa also has a thick blunt quadrangular stem and three-compound leaves, which makes it easy to identify.

But the most famous thing about Bidens pilosa is its fruit. The small achenes have thorns that can easily stick to clothes and hair, which not only makes people feel prickly, but also takes a long time to pick them clean. Such an annoying plant was listed on the "List of Invasive Alien Species in China" in 2014.

Probably some childhood prank tool from some friends. | Dinesh Valke / Wikimedia Commons

Five-clawed golden dragon

Ipomoea cairica is another common invasive plant in southern my country. It is related to sweet potatoes and water spinach, and is sometimes mistaken for morning glory. The plant may be native to Africa or tropical Asia, but thanks to its excellent growth ability, Ipomoea cairica has now taken root in many parts of the world.

Five-clawed golden dragon | John Robert McPherson / Wikimedia Commons

The leaves of the five-clawed golden dragon are very dense. It grows as a vine and covers other plants, eventually causing the other plants to die because they cannot get enough sunlight.

The same genus, petunia I. purpurea, is also an invasive species｜Cbaile19 / Wikimedia Commons

Alternanthera philoxeroides

Alternanthera philoxeroides is native to South America. Like water hyacinth, it was originally used as feed. Livestock do not like to eat it, but Alternanthera philoxeroides has long escaped into the wild.

Alternanthera philoxeroides｜USDA

The wild Alternanthera philoxeroides has caused a lot of trouble - they can survive on land and water simply by relying on their powerful asexual reproduction. The branches of Alternanthera philoxeroides can grow adventitious roots at the nodes, and can grow into new plants after being broken. They can spread on the ground, and can also float on the water surface by relying on the cavities in the stems, eventually blocking the waterway and affecting the growth of other organisms in the water.

Affecting the growth of other organisms in the water｜Harry Rose / Alternanthera philoxeroides habit5c

What to do if you encounter an invasive species

The above are only some of the plants in the "List of Alien Invasive Species in China". Based on agricultural production, the Ministry of Agriculture and Rural Affairs has also issued the "List of National Key Alien Invasive Species", which includes 52 alien invasive species . In addition, there are some species that have already formed an invasion trend but the impact is not serious, which are also included in the list of alien invasive species, illustrations and annals. We must also remain vigilant about these species.

Now, biological invasion research institutions have established different types of alien invasive species information systems, so we can keep up with the relevant information of invasive species. Among them, the China Alien Invasive Species Information System (https://www.iplant.cn/ias/) has added an image recognition function, which greatly facilitates species identification.

Home Page of Information System of Invasive Alien Species in China (IASC)

What should we do when we find invasive plants? The most important thing is to find and eliminate them early to minimize their impact on the ecological environment. At present, our commonly used prevention measures are mainly to strengthen customs inspection and quarantine of plants, and the control measures mainly rely on manual removal and chemical weeding machine spraying.

As for individuals, do not bring in living plants, seeds or soil from abroad at will ; if you see invasive plants in your daily life, you can also eradicate them at will - but the premise is that you can be sure that this is an invasive plant, and never harm native plants by mistake.

It’s a good idea to remove invasive plants without accidentally harming native plants | Couleur / Pixabay

However, these measures often have omissions, which can easily lead to a "resurrection". One way to avoid a resurgence is to use native species to restore the ecosystem as soon as possible after clearing out invasive species, so that more native species have the opportunity to grow.

As the saying goes, "a fortress is easily breached from within." A perfect and balanced ecosystem usually does not give invasive species too many opportunities, and biological invasions are more likely to occur in damaged ecosystems or artificially controlled ecosystems . Therefore, if we get rid of existing invaders and build a new fortress composed of native species, future invasive species will become more obedient.

Author: I don’t know plants

Editor: Mai Mai

This article comes from the Species Calendar, welcome to forward

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