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Shield-fern Rhizome is the dried rhizome and petiole remnants of Dryopteris crassirhizoma Nakai, a plant of the Dryopteridaceae family, officially named male fern rhizome. It is mainly produced in Heilongjiang, Jilin, Liaoning, and other provinces.

Materia medica research suggests that the varieties of Shield-fern Rhizome have been extremely confused throughout history. Ferns became the mainstream medicinal plants starting from the Six Dynasties, but the varieties used varied by region. Among them, the japonica china fern rhizome of the Cibot Rhizome category has a relatively long history of use and is likely the dominant variety of Shield-fern Rhizome in ancient times. However, because Shield-fern Rhizome has always been used in Chinese medicine as a worm-killing agent, the Bencao Jing states that it "kills three types of worms," and the Baopuzi, Inner Chapter, Volume 5, says: "Huanlu Shield-fern Rhizome kills nine types of worms, and Chinese Angelica Peony Root relieves colicky pain." Pharmacological studies have confirmed that among various Shield-fern Rhizome materials, only Dryopteris crassirhizoma Nakai contains phloroglucinol compounds with significant anthelmintic effects. Therefore, this plant is now considered the authentic variety, mainly produced in the three northeastern provinces.

bubble_chart Variety Identification

The name Shield-fern Rhizome first appeared in the "Erya·Shi Cao": "Bianfu, Zhiluo, Shield-fern Rhizome." In the Bencao Jing, Shield-fern Rhizome is listed as a lower-grade herb, stating: "It tastes bitter, slightly cold, and is toxic. It treats pathogenic heat in the abdomen, various toxins, and kills three types of worms. It is also known as Guanjie, Guanqu, Baitou, Hujuan, and Bianfu." Although the Bencao Jing's records are brief, there are still clues to follow. According to the Bencao Jing's "also known as Hujuan," Sen Ritsuki's Bencao Jing commentary states: "Juan is a borrowed term for fist, as the young leaves resemble a clenched hand with raised fuzz, hence the name Hujuan." The "Erya Yi" states: "Ferns grow like a child's fist, purple and plump." The "Pi Ya" states: "Ferns resemble the curled feet of a large bird or the stumbling of a human foot." Like "Hujuan," these descriptions refer to the unique curled form of young fern leaves, confirming that the Bencao Jing's Shield-fern Rhizome is indeed a fern. Moreover, in the Bencao Jing, Shield-fern Rhizome has the alias "Baitou," similar to another fern, Cibot Rhizome, which is also known as "Baizhi" in the Bencao Jing, describing its clustered leaf state. As Li Shizhen stated in the Bencao Gangmu: "Its root has one main stem with many branches, hence the plant is called Phoenix Tail, and the root is called Shield-fern Rhizome, Guanjie, Guanqu." However, its specific variety cannot be definitively determined.

Strangely, the "Shield-fern Rhizome" mentioned in Wei-Jin literature seems to refer to a seed plant. For ease of discussion, the relevant Wei-Jin literature on Shield-fern Rhizome is briefly listed below:

The "Guangya" states: "Guanjie is Shield-fern Rhizome."

The "Erya" Guo Pu commentary states: "Leaves are round and sharp, stems are black and hairy, spread on the ground, and do not die in winter. Also known as Guanqu. The Guangya calls it Guanjie."

The Mingyi Bielu states: "Shield-fern Rhizome removes tapeworms, breaks abdominal masses, eliminates head wind, and stops bleeding from wounds. Its flowers treat malignant sores and cause diarrhea. Also known as Boping, Lezao, and Caozhitou. It grows in Xuanshan Valley, Yuanju, and Shaoshi Mountain. The roots are harvested in February and August and dried in the shade."

The "Wu Pu Materia Medica" states: "Shield-fern Rhizome is also known as Guanlai, Guanzhong, Qumu, Guanzhong, Boqin, Yaozao, Bianfu, and Huangzhong. Its leaves are green-yellow and paired, stems are black and hairy, and it does not die in winter or summer. It blooms white in April, bears black fruit in July, and grows in clusters. The roots are harvested in March and August, and the leaves are harvested in May."

It is noteworthy that both Bielu and "Wu Pu" mention that Shield-fern Rhizome has flowers, and "Wu Pu" also states that it bears black fruits, which clearly indicates it is a seed plant rather than a fern. As for Guo Pu's annotation, although it does not explicitly mention flowers or fruits, the plant characteristics he describes, such as stems with black hairs, evergreen small herbs, and ground-covering growth, are largely similar to those in "Wu Pu," suggesting they refer to the same plant.

However, starting from the Bencao Jing Jizhu, ferns once again became the mainstream of medicinal Shield-fern Rhizome. Tao Hong-jing said: "Shield-fern Rhizome is also found near the roads. Its leaves resemble large ferns, and its roots, color, and hair are entirely like an old owl's head, hence it is called the grass owl's head." The so-called "large fern" should refer to a large type of fern. In the "Book of Songs · Zhao Nan · Grass Insects," it says, "Ascend that southern mountain, and gather its ferns." According to the "Qi Min Yao Shu," in the "Method of Making Pickled Vegetables, Number Eighty-eight," quoting the "Shi Yi Shu," it says: "Ferns are mountain vegetables. When they first sprout, they resemble garlic stems, purple-black in color. In the second month, they grow to eight or nine inches tall, and when old, they have leaves. When boiled, they are smooth and delicious like mallows... In the third month, their tips split into three branches, each with several leaves, resembling Sweet Wormwood, long, thick, and strong, inedible." The fern in the "Book of Songs" is a plant of the Dennstaedtiaceae family, with leaves that are three to four times pinnately divided. This is the first time in literature that Shield-fern Rhizome is truly associated with ferns. Although Tao Hong-jing's description still does not help in understanding the species of Shield-fern Rhizome, his statement that the leaves resemble large ferns, i.e., multiple times pinnately divided, sets the stage for later literature to describe Shield-fern Rhizome leaves as resembling phoenix tails.

The "Xin Xiu" entry on Shield-fern Rhizome entirely follows the old text of Bencao Jing Jizhu, without any additions. However, in the entry on Cibot Rhizome, Su Jing says: "(Cibot Rhizome) seedlings resemble Shield-fern Rhizome." Additionally, a Tang Dynasty Taoist scripture collected in the "Zhengtong Daozang," under the category of various arts in the Dong Shen section, titled "Chunyang Zhenren Yaoshi Zhi," provides a detailed description of the original plant of Shield-fern Rhizome. The book refers to Guan Zhong (i.e., Shield-fern Rhizome) as Five Phoenix Dragon Sprout, with a poem saying: "Five Phoenixes often grow in deep ravines, growing tall in clusters. They are only picked in the fifth month and mid-autumn, resembling the wings and tails of phoenixes." Judging from the leaf shape, this variety is definitely not Osmunda japonica. Notably, starting from this book, the Five Dynasties' Han Bao-sheng's "Shu Bencao" and the Song Dynasty's Su Song's "Bencao Tujing" both mention that Shield-fern Rhizome leaves resemble phoenix tails.

The "Shu Bencao · Tujing" says: "Shield-fern Rhizome, seedlings resemble Cibot Rhizome, shaped like pheasant tails, roots straight with many branches, skin black and flesh red, curved ones are called grass owl heads, now found in shady mountain valleys."

The "Bencao Tujing" says: "Shield-fern Rhizome is now found in Shaanxi, Hedong prefectures, and between Jing and Xiang, but few have flowers. In spring, red seedlings grow, leaves large like ferns, stems triangular, leaves green like small chicken feathers, also known as Chinese brake herb. Roots are purple-black, shaped like large gourds, with black hairy roots, resembling old owls."

Although the above two illustrated classics have similar descriptions of Shield-fern Rhizome's morphology, the varieties may not be the same. The "Shu Bencao" records a Sichuan-produced drug, with seedlings resembling Cibot Rhizome, and its rhizomes are upright and cylindrical, likely the Woodwardia japonica (L.f.) Sm. of the Blechnaceae family, commonly used in Sichuan, or the same genus's W. unigemmata (Makino) Nakai. According to research, these two varieties are the original plants of Chengde Army Cibot Rhizome and Meizhou Cibot Rhizome in the "Bencao Tujing."

The texts on Shield-fern Rhizome and Cibot Rhizome in the "Bencao Tujing" can be cross-referenced. The entry on Cibot Rhizome says: "Seedlings are pointed and finely divided, green, about a foot tall, without flowers, stems and leaves resemble Shield-fern Rhizome but are finer." Comparing the medicinal illustrations of Zizhou (now Zichuan, Shandong) Cibot Rhizome and Zizhou Shield-fern Rhizome in the "Bencao Tujing," it can be seen that both have thick rhizomes covered with scales, but Cibot Rhizome spreads horizontally, while Shield-fern Rhizome stands upright. Cibot Rhizome has three times pinnately compound leaves, while Shield-fern Rhizome has twice pinnately divided leaves. Although these characteristics are not sufficient to determine their original plants, combined with the "Tujing" mentioned locations "Shaanxi, Hedong prefectures, and between Jing and Xiang," Mr. Xie Zongwan believes that "the original plants of Shield-fern Rhizome: Dryopteris, Matteuccia, Athyrium, and Woodwardia plants' underground parts are close to this." His argument is very reasonable.

Most materia medica from the Ming and Qing dynasties, when describing the original plant of Shield-fern Rhizome, compiled previous literature and rarely conducted field investigations. Therefore, their records are often riddled with errors. For example, Lu Zhi-yi's "Materia Medica Chengya Banji" from the Ming Dynasty states: "It grows in the valleys of Xuan Mountain, Yuanju, and Shaoshi Mountain. Nowadays, it is commonly found in Shaanxi, Hedong prefectures, and the regions of Jing and Xiang. It grows in shady areas near water, surviving through winter and summer. Multiple roots grow in clusters, each root having multiple stems. The stems are triangular, resembling ferns, and contain a black, slippery sap. The leaves grow in pairs, resembling chicken feathers or phoenix tails, similar to Cibot Rhizome leaves but without serrated edges. The leaves are greenish-yellow, darker on the surface and lighter on the back. In April, the flowers are white; in July, the fruits are black, clustered and coiled, with roots growing sideways, curved and pointed, with black fibrous roots resembling those of Cibot Rhizome and the shape of a crouching owl. The skin is black, the flesh is red, straight and branched, resembling a hundred heads." This description is actually a compilation from "Mingyi Bielu," "Wu Pu's Materia Medica," "Bencao Tujing," and "Bencao Gangmu." Such a description makes it difficult to understand the details clearly.

Not only is the general clinical materia medica so, but the records in the Bencao Gangmu are also quite vague. Li Shi-zhen said: "Shield-fern Rhizome mostly grows in shady, near-water areas of mountains. Several roots grow in clusters; one root has several stems, the stems are as large as chopsticks, and their sap is slippery; the leaves grow in pairs, like the leaves of Cibot Rhizome but without serrations, green-yellow in color, darker on the surface and lighter on the back; the roots are curved with a pointed tip, black whiskers clustered together, also similar to the roots of Cibot Rhizome but larger, shaped like a crouching owl." From the description "like the leaves of Cibot Rhizome but without serrations," this variety might refer to Osmunda japonica Thunb. of the Osmundaceae family, but the attached medicinal illustration in the Gangmu greatly differs from Osmunda japonica. Moreover, the Bencao Gangmu's Shield-fern Rhizome prescription for postpartum blood loss, as cited in Furen Liangfang, states: "Use one Shield-fern Rhizome shaped like a hedgehog, use it whole without cutting, just rub off the hair and calyx." The so-called "calyx" actually refers to the scales on the rhizome of Shield-fern Rhizome. Although this is a citation from others in the Gangmu, it indeed reflects Li Shi-zhen's lack of precise understanding of the original plant of Shield-fern Rhizome.

In contrast, the descriptions of Shield-fern Rhizome in Lan Mao's Diannan Bencao from the Ming dynasty and Wu Qi-jun's Zhiwu Mingshi Tukao from the Qing dynasty are more accurate. Their original plants have been identified as Cyrtomium caryotideum (Wall) Presl. of the Dryopteridaceae family and Cyrtomium fortunei J. Smith, respectively. However, these two varieties are almost never used as Shield-fern Rhizome in commercial medicinal materials.

Although there are many sources of Shield-fern Rhizome in the domestic market today, the relatively concentrated varieties are japonica china fern rhizome of the Woodwardia genus, male fern rhizome of the Dryopteris genus, and japanese flowering fern rhizome of the Osmundaceae genus. From the materia medica考证, it can be seen that the use of japonica china fern rhizome has a relatively long history, and in the Ming and Qing materia medica, Shield-fern Rhizome was directly referred to as "black Cibot Rhizome," indicating it was the mainstream medicinal variety at that time.

As for Osmunda, its name appears in the "Erya," which states: "Qi, Yue Er." Guo Pu's annotation: "That is Zi Qi. It resembles a fern and is edible." The "Guangya" states: "Zi Qi, fern." Thus, it is known that "Zi Qi" had a specific name in ancient times, and the plant Osmunda not only has a unique leaf shape but also its rhizome is not covered with scales, which is an important feature distinguishing it from other Shield-fern Rhizomes. Starting from Tao Hong-jing, it was said that the leaves of Shield-fern Rhizome resemble a phoenix tail. Further analyzing the processing requirements for Shield-fern Rhizome in medical prescriptions, Puji Benshi Fang mentions "scraping off the black skin," Yixue Rumen says "removing skin and hair," and Furen Liangfang states "rubbing off the hair and calyx," none of which match the characteristics of japanese flowering fern rhizome. Therefore, the historical use of Osmunda as Shield-fern Rhizome still requires further research. Like Osmunda, Mianma also appears in the "Erya," which states: "Mianma, sheep tooth." Guo's annotation: "The grass is fine, the leaves grow in a spiral and are hairy, resembling sheep teeth. Nowadays, it is called Yanchi in Jiangdong. Silk reelers use it to extract cocoon threads." This has nothing to do with the male fern rhizome used today.

It should be noted that due to the relatively small differences among fern species and the often vague descriptions of plant morphology in ancient literature, the考证 of varieties becomes more difficult. Through materia medica考证, the Shield-fern Rhizome used in ancient times can be divided into two categories based on the shape of the medicinal material. One category, as Han Bao-sheng described, has "straight roots with many branches," which, as mentioned earlier, mainly refers to japonica china fern rhizome. The other category, as Tao Hong-jing described, "resembles an old owl's head," or as Su Song described, "shaped like a large melon," clearly does not originate from the Blechnaceae family, but its original plant is difficult to确考, and male fern rhizome, japanese flowering fern rhizome, etc., may also be included.

bubble_chart Historical Evolution of Authentic Medicinal Materials

The Mingyi Bielu states: "It comes from the valleys of Xuanshan, Yuanju, and Shaoshi Mountain." As mentioned earlier, this type of Shield-fern Rhizome differs significantly from what is used today. Although Shield-fern Rhizome is a type of fern, its variety is not the same as today's male fern rhizome, and thus it need not be discussed further.

Currently, the genuine product used is Dryopteris crassirhizoma from the Dryopteridaceae family, mainly distributed in Heilongjiang, Jilin, Liaoning, and parts of Hebei. This is quite different from the recorded origin of Shield-fern Rhizome in historical materia medica. For a long time, this species might have been only a folk remedy in the Northeast. The reason it became a mainstream variety in modern times is likely related to the discovery by chemists and pharmacologists of phloroglucinol components with anthelmintic activity.