Introduction of Zi Cao: Arnebia Root, Gromwell Root
✵This article documents the herb Arnebia Root (Gromwell Root), including its English name, Latin name, Pinyin name, properties and flavor, botanical sources—two plant species: (1) Arnebia euchroma (Royle) Johnst. and (2) Lithospermum erythrorhizon Sieb.et Zucc.—with detailed descriptions of their botanical features, growth characteristics, ecological environments, characteristics of the dried root, pharmacological actions, medicinal efficacy, and administration guidelines.
Radix Arnebiae seu Lithospermi (Arnebia Root or Gromwell Root)
Pinyin Name: Zǐ Cǎo
English Name: Arnebia Root or Gromwell Root
Latin Name:Radix Arnebiae seu Lithospermi Property and Flavor: Cold; bitter
Brief Introduction:Radix Arnebiae seu Lithospermi is the dried root of Arnebia euchroma (Royle) Johnst. or Lithospermum erythrorhizon Sieb.et Zucc., used clinically to promote eruption in measles and applied externally for burns, frostbite, dermatitis, and eczema. It is commonly known as Radix Arnebiae seu Lithospermi, Arnebia Root, Gromwell Root, or Zǐ Cǎo.
Botanical Source:Radix Arnebiae seu Lithospermi is the dried root of Arnebia euchroma (Royle) Johnst. or Lithospermum erythrorhizon Sieb.et Zucc. Both are perennial herbs belonging to the genus Lithospermum, family Boraginaceae (borage or forget-me-not family), order Boraginales. The two principal species are described below:
(1) Lithospermum erythrorhizon Sieb.et Zucc.
Botanical Description:Lithospermum erythrorhizon Sieb. et Zucc. is also known as Lithospermum officinale L. subsp. erythrorhizon (Sieb. et Zucc.) Hand.-Mazz. It is a member of the Boraginaceae family and the genus Lithospermum. Common names include Lithospermum erythrorhizon, Zǐ Cǎo, Zǐ Dān, Zǐ Cǎo Gēn (Purple Grass Root), and Yīng Zǐ Cǎo. A perennial herb reaching 50–90 cm in height, it bears a thick, hypertrophied, conical, slightly curved, and often branched root with a violet-red (purple-red) outer cortex. The stem is erect, cylindrical, unbranched or sparsely branched in the upper portion, and densely covered with stiff, white bristles. Leaves are alternate, sessile, with oblong-lanceolate to ovate-lanceolate blades measuring 3–8 cm long and 5–17 mm wide; apex is acuminate, base is cuneate, margins are entire; both surfaces are strigose (covered with appressed, stiff hairs).
The inflorescence is a botrytic cyme, terminal or axillary. Flowers are small and hermaphroditic. Floral bracts are lanceolate or narrowly ovate, ~3 cm long, with coarse hairs on both surfaces. The calyx is 5-parted near the base; lobes are linear, ~4 mm long. The corolla is white, fistulose (tubular), 6–8 mm long; the apex is 5-lobed, with broad-ovate, spreading lobes; the throat appendage is hemispherical with a slightly concave apex. There are five stamens inserted slightly above the middle of the corolla tube; filaments are ~0.4 mm long and inserted at the mid-corolla level; anthers measure 1–1.2 mm in length. The ovary is 4-lobed; the style is linear, 2–2.5 mm long; the stigma is globular and 2-lobed.
The fruit is a schizocarp composed of four ovoid nutlets, each ~3 mm long, ash-gray (grayish-white) or fawn (yellowish-brown), smooth, glossy, and containing one seed each. Flowering occurs from June to August; fruiting from August to September.
Ecological Environment: Lithospermum erythrorhizon grows on sunny mountain slopes, in grasslands, shrublands, and along forest margins.
Growth Characteristics: Lithospermum erythrorhizon is cold-tolerant but heat-sensitive and intolerant of waterlogging. It thrives best in calcareous loam, sandy loam, or clay loam soils.
Characteristics of the Herb: The dried root of Lithospermum erythrorhizon Sieb. et Zucc is also known as hard gromwell root. It is conical, twisted, and branched, 7–14 cm long and 1–2 cm in diameter. The surface is purplish-red or purplish-black, rough with longitudinal ridges; the cortex is thin and easily exfoliated. The texture is hard and brittle, fracturing readily; the fractured surface shows a deep purple cortex and a large, grayish-yellow xylem (wood) portion. The herb has a distinctive odor and tastes slightly sour and sweet.
Pharmacological Actions: (1) Contraceptive effect; (2) Effects on the circulatory system; (3) Other effects: mild antipyretic activity; enhanced tone and contractility of the small intestine.
Medicinal Efficacy: Cools blood, activates blood, detoxifies, and promotes eruption. It is indicated for blood-heat and excessive toxicity, maculae, purplish-black maculae, measles, measles with poor eruption, hematemesis, epistaxis (nosebleed), hematuria, purpura (including petechiae and ecchymoses), jaundice, ulcers, cutaneous swelling and ulceration, eczema, burns caused by scalding liquids or fire.
Administration of Radix Arnebiae seu Lithospermi (Zǐ Cǎo):
Reference:
Administration Guide for Radix Arnebiae seu Lithospermi (Zǐ Cǎo)
TCM Books:
(1) Internally: 5–9 grams. Externally: appropriate amount, prepared as a paste or infused in vegetable oil and applied topically; (2) Internally: Water decoction, 1–3 qián (≈3–9 grams), or prepared as pills or powder; Externally: prepared as a paste and applied topically; (3) Internally: Water decoction, 3–9 grams, or prepared as powder; Externally: appropriate amount, prepared as a paste or oil-based paste and applied topically.
(2) Arnebia euchroma (Royle) Johnst.
Botanical Description:Arnebia euchroma (Royle) Johnst. is also known as Lithospermum euchroma Royle. It is a perennial herb of the family Boraginaceae (borage or forget-me-not family) and genus Arnebia. Common names include Arnebia euchroma, Arnebia Root, and Ruǎn Zǐ Cǎo ("Soft Arnebia Root"). The plant grows 15–40 cm tall. The entire plant is covered with white or pale-yellow (light-yellow) stiff, appressed hairs. The root is stout and slightly conical; the root head and several lateral roots often become entangled. The outer cortex is dark reddish-purple. The stem is erect, usually solitary, or dichotomously branched at the base; the base bears a stem sheath formed by persistent leaf bases. Basal leaves are tufted, linear-lanceolate or linear, 5–20 cm long and 5–15 cm wide—with a short-acuminate apex and a sheath-forming base; margins are entire. Cauline leaves are linear-lanceolate, acuminate, lacking a sheath, and sessile.
Drepanium arise densely from the axils of stem leaves, 2–6 cm long. Flowers are hermaphroditic. Floral bracts are foliaceous (leaf-like) and lanceolate, covered with stiff hairs. The calyx is short, tubular, and 5-lobed; lobes are narrowly strip-shaped, with both surfaces densely covered in pale-yellow (light-yellow) bristles. The corolla is tubular-campanulate, purple or mauve (lilac), 1–1.5 cm long; lobes are elliptic and spreading; the exterior is sparsely covered with white hairs; the throat and base are glabrous and lack appendages. There are five stamens; filaments are short or absent, inserted at the middle of corolla tube or corolla throat; the ovary is 4-parted; the style is slender, with a 2-lobed apex and 2 obovate stigmata.
The nutlets are broad-ovate, brown, 3.5 mm long and about 3 mm wide, bearing a coarse reticulated pattern and a few warty protrusions. The flowering period is from June to July, and the fruiting period is from August to September.
Ecological Environment: Arnebia euchroma (Royle) Johnst grows on gravelly hillsides, grasslands, and grassy marshlands at altitudes of 2,500–4,200 m above sea level.
Characteristics of the Herb: The dried root of Arnebia euchroma (Royle) Johnst is also known as soft gromwell root. The roots are irregularly long-cylindrical, mostly twisted, 7–20 cm long and 1–2.5 cm in diameter. The surface is purplish-red or purplish-brown, and the root cortex is loose and strip-shaped, often comprising over 10 overlapping layers that peel off easily. Some specimens show divergent stem residues at the upper end. The herb is soft; its texture is loose and pliable, and it breaks easily. The fracture surface is irregular, and the xylem (wood part) is small, yellow or yellowish-white. The herb has a distinctive odor and tastes slightly bitter and astringent.
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References:
1. Introduction of Zi Cao: Arnebia Root, Gromwell Root
✵This article documents the herb Arnebia Root (Gromwell Root), including its English name, Latin name, Pinyin name, properties and flavor, botanical sources—two plant species: (1) Arnebia euchroma (Royle) Johnst. and (2) Lithospermum erythrorhizon Sieb.et Zucc.—with detailed descriptions of their botanical features, growth characteristics, ecological environments, characteristics of the dried root, pharmacological actions, medicinal efficacy, and administration guidelines.
Pinyin Name: Zǐ Cǎo
Botanical Description: Lithospermum erythrorhizon Sieb. et Zucc. is also known as Lithospermum officinale L. subsp. erythrorhizon (Sieb. et Zucc.) Hand.-Mazz. It is a member of the Boraginaceae family and the genus Lithospermum. Common names include Lithospermum erythrorhizon, Zǐ Cǎo, Zǐ Dān, Zǐ Cǎo Gēn (Purple Grass Root), and Yīng Zǐ Cǎo. A perennial herb reaching 50–90 cm in height, it bears a thick, hypertrophied, conical, slightly curved, and often branched root with a violet-red (purple-red) outer cortex. The stem is erect, cylindrical, unbranched or sparsely branched in the upper portion, and densely covered with stiff, white bristles. Leaves are alternate, sessile, with oblong-lanceolate to ovate-lanceolate blades measuring 3–8 cm long and 5–17 mm wide; apex is acuminate, base is cuneate, margins are entire; both surfaces are strigose (covered with appressed, stiff hairs).
Characteristics of the Herb: The dried root of Lithospermum erythrorhizon Sieb. et Zucc is also known as hard gromwell root. It is conical, twisted, and branched, 7–14 cm long and 1–2 cm in diameter. The surface is purplish-red or purplish-black, rough with longitudinal ridges; the cortex is thin and easily exfoliated. The texture is hard and brittle, fracturing readily; the fractured surface shows a deep purple cortex and a large, grayish-yellow xylem (wood) portion. The herb has a distinctive odor and tastes slightly sour and sweet.
Botanical Description: Arnebia euchroma (Royle) Johnst. is also known as Lithospermum euchroma Royle. It is a perennial herb of the family Boraginaceae (borage or forget-me-not family) and genus Arnebia. Common names include Arnebia euchroma, Arnebia Root, and Ruǎn Zǐ Cǎo ("Soft Arnebia Root"). The plant grows 15–40 cm tall. The entire plant is covered with white or pale-yellow (light-yellow) stiff, appressed hairs. The root is stout and slightly conical; the root head and several lateral roots often become entangled. The outer cortex is dark reddish-purple. The stem is erect, usually solitary, or dichotomously branched at the base; the base bears a stem sheath formed by persistent leaf bases. Basal leaves are tufted, linear-lanceolate or linear, 5–20 cm long and 5–15 cm wide—with a short-acuminate apex and a sheath-forming base; margins are entire. Cauline leaves are linear-lanceolate, acuminate, lacking a sheath, and sessile.
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