You may not have thought that the Fern Scholars are also so involuted.

(Photo credit: Zhang Xianchun and Liu Baodong)

In today's era, if we mention the word "involution", it will inevitably make people feel anxious and confused. However, there is a kind of plant on the earth that has been growing tenaciously in the dense forests of mountains with its "involution" posture for billions of years, showing infinite vitality. They are ferns.

Ferns, which have no flowers or fruits, may not be very eye-catching among the 400,000 species of higher plants on the green planet. But if you focus your attention on them, you will find that they are almost everywhere in the forest in their young stages, jumping and agile; when they grow up, they are deep and rich, full of an ancient and mysterious atmosphere that seems to be independent of the world, which makes more and more people succumb to "ferns". Today, let us approach the mysterious world of ferns and understand their different "involutionary life".

Alsophila costularis

(Photo credit: Zhang Xianchun)

Sphaeropteris brunoniana

(Photo credit: Zhang Xianchun)

Platycerium wallichiana

(Photo credit: Zhang Xianchun)

Dipteris chinensis

(Photo credit: Zhang Xianchun)

Lepisorus fortunei

(Photo credit: Zhang Xianchun)

Pteridium aquilinum subsp.japonicum

(Photo credit: Zhang Xianchun)

Part 1

One-shot identification of ferns

Even though ferns have a different primitive atmosphere from flowering plants, people still cannot easily identify them. However, it is worth noting that in the process of evolution, nature has endowed ferns with a unique feature, that is, young leaves that curl like question marks. This feature allows us to go to the mountains and fields in any part of the world. As long as we see a plant holding a big question mark and asking you: "Who am I?" At this time, we might as well boldly say: "You are a fern."

Fist Roll Collection

(Photo credit: Zhang Xianchun and Liu Baodong)

Dr. Gu Yufeng observing in the wild

Cibotium barometz

(Photo credit: Liu Baodong)

Plagiogyria glauca

(Photo credit: Zhang Xianchun)

Cyclosorus crinipes (left)

Histiopteris incisa (right)

(Photo credit: Zhang Xianchun)

However, there are a few species of ferns that do not have this feature, such as bottle grass and aquatic ferns such as Sophora japonica and Azolla, as well as primitive small-leaf ferns such as Lycopodiella and Selaginella. In this case, other characteristics are needed to assist in identification.

Ophioglossum vulgatum (left)

Lycopodium japonicum (middle)

Selaginella iridescens (right)

(Photo credit: Zhang Xianchun)

When the leaves of ferns sprout, they look like tightly clenched fists. This phenomenon is called "fist curling". As the leaves grow longer, these fists will gradually stretch out and "transform" into leaves of various shapes. This kind of curled young leaves often appear on the covers of major magazines due to its beautiful geometric structure, and has almost become an important identity symbol of ferns.

Dryopteris crassirhizoma

(Photo credit: Zhang Xianchun)

So perhaps everyone will wonder why fist-curled leaves have become a common choice for ferns and what is their significance?

Scientists have many explanations for this, but it is generally believed that the curled leaves can protect the fragile top growth part of the fern and defend against insects. At the same time, the cilia and scales on some curled leaves can also reduce external damage and retain water and keep out the cold. Different groups of ferns have different cilia or scales, which is a good identification feature in the wild.

Unique fist curled leaves

(Photo credit: Zhang Xianchun)

The various curled leaves are like elves, bringing the breath of spring and bringing agility to the quiet forest in early spring. In midsummer, they stretch out, showing green leaves of various shapes but symmetrical. The leaf shapes are complex and varied - simple leaves, binary fission, trilobate, palmate fission, and even single leaves with one or more pinnate fissions; there are also more tortuous and delicate single pinnate compound leaves, etc. The backs of these leaves give birth to multiple sporangia of various colors like insect eggs, which gather into sporangia, and then produce spores for the reproduction of ferns.

Single leaf (left)

Palmate cleavage (middle)

One feather (right)

Bipinnate (left)

Bipinnate-pinnate pinnae (medium)

Tripinnate (right)

Four pinnates (left)

Five pinnates (right)

Spore leaves of Arachniodes rhomboidea

(Photo source: All 9 photos were taken by Zhang Xianchun)

Most ferns will develop 64 spores in the sporangium. When the spores mature, the annular cells on the outer shell of the sporangium use the tension of water movement to shoot out the internal spores like a crossbow. The spores germinate and reproduce new plants under conditions of water and suitable temperature and humidity. A new generation of curled young leaves break through the soil again, quietly completing a life cycle. These green elves continue to reproduce endlessly.

A life of alternating generations

(Source: Quoted from "Chinese Lycopodiella and Ferns" by Zhang Xianchun)

The first leaf of the fern embryo looks like a baby in its mother's belly.

(Photo credit: Liu Baodong)

Part 2

Wild vegetables in the mountains, the taste of fern on the tip of the tongue

As early as in the Book of Songs, there was a description: "Climbing the steep southern mountain, picking ferns". The fist-shaped leaves (young leaves) of some ferns are famous wild vegetables, such as the pod fern (cucumber-scented), chestnut fern, duncula, purple fern, Chinese hoof-covered fern (monkey leg), vegetable fern (belonging to the genus Diplocarpus in the family Pteridaceae), etc.

Matteuccia struthiopteris (left)

Histiopteris incisa (Medium)

Dicranopteris linearis (right)

(Photo credit: Zhang Xianchun)

Osmunda japonica (left)

Diplazium esculentum (right)

(Photo credit: Zhang Xianchun)

Dark green short-bowel fern Diplazium viridissimum (left)

Pteridium aquilinum subsp.japonicum (right)

Dicranopteris linearis

(Photo credit: Zhang Xianchun and Sun Jiuqiong)

Among them, the ferns of the genus Pteris in the Pteris family are rich in nutrients, containing more than 16 kinds of amino acids and a variety of trace elements. They have high edible and medicinal value and are known as "longevity vegetables". They are also the best-selling and most exported variety of wild vegetables, and one of the most competitive wild vegetables in the international market.

Fern Pteridium aquilinum subsp. japonicum mature plant

(Photo credit: Zhang Xianchun)

Part 3

How can you eat delicious bracken?

First of all, the picking period should not be underestimated. It is best to pick bracken when the curled leaves grow about 20 cm above the ground and the new top leaves have not yet unfolded. Harvesting too early will result in low yields, while harvesting too late or high temperature and drought will cause the cellulose in the stems to age, affecting the edible quality.

Fern Pteridium aquilinum subsp. japonicum Fist and leaf curling period

(Photo credit: Li Dong)

Secondly, the way of eating is very important. People often use fresh and dried products to cook dishes and make soups. Before eating, they should be boiled in boiling water and then soaked in cold water to remove the odor before eating, but they can be eaten in excess. In addition to edible young leaves, the underground rhizomes of ferns are rich in starch, which can be extracted and processed to make the popular appetizer "fern root powder".

It can be seen that although the flavor of ferns is not the best among all edible ferns, it has become the most common fern on the tables of the general public due to its wide distribution and diverse cooking methods.

Bracken

(Photo credit: Sun Jiuqiong)

Fern root powder

(Photo credit: Sun Jiuqiong)

Part 4

Fresh and natural wind, beauty from ancient times

The fist-curled leaves (young leaves) of ferns are not only edible, but also have a high appreciation value. Ferns have become the leaf material favored by flower shops and many florists due to their high appearance and unique temperament. In addition to bouquets and wreaths, ferns can also be the best supporting role in weddings and gatherings. Their fresh green can make people relax and enjoy comfort.

Study, dining room, balcony... No matter where you are, as long as you have a simple pot of fern, you don't have to be too particular about its placement, just let it grow freely, it can create a peaceful, elegant and simple state of mind for people.

Dicranopteris dichotoma fist leaf curl (left)

Fern Fist Curl Leaf (right)

(Photo credit: Sun Jiuqiong)

Artwork made from the curled leaves of Dictyophora dichotoma (left)

Fist-curled leaf pattern scarf (right)

(Photo credit: Sun Jiuqiong)

Small ornaments made from the dried leaves of Dictyophora dichotoma

(Photo credit: Sun Jiuqiong)

At present, the most famous organization in China related to the study of ferns is the "Fern Association", namely the Chinese Fern Association. Since its establishment in 1987, it has developed into three branches of the association, namely the Fern Branch of the China Flower Association, the Fern Professional Committee of the China Wild Plant Protection Association, and the Fern Professional Committee of the Chinese Botanical Society.

The emblem of the Fern Association was also inspired by the curled leaf shape. The right picture is created with more than 100 specimens of ferns surrounding the emblem's curled leaf pattern. This work is also the largest single embossed work in China (230cmX110cm in height) and is kept in the office of the Fern Branch of the China Flower Association.

Illustration by Li Aili (left)

Photographed by Li Zexin (created by Liu Yi, Sun Jiuqiong and Zhao Xiaoling) (right)

Conclusion

Ferns, these green elves that have come from the long river of time, quietly release greenery with their slightly curled leaves in the corners of human life, and witness the development of civilization and the change of times in the most quiet way...

Swamp Fern Thelypteris palustris

(Photo credit: Zhang Xianchun)

Produced by: Science Popularization China

Author: Sun Jiuqiong (Institute of Botany, Chinese Academy of Sciences)

Reviewer: Zhang Xianchun and Li Zhongyang (Institute of Botany, Chinese Academy of Sciences, Gannan Normal University)

Editor: Sun Chenyu

Producer: China Science Expo

This article only represents the author's views and does not represent the position of China Science Expo

This article was first published in China Science Expo (kepubolan)

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