Introduction of Bai Wei: Blackened Swallowwort Root
✵The article documents the herb Blackened Swallowwort Root, including its English name, Latin name, Pinyin name, properties and flavor, botanical sources—two plant species: (1) Cynanchum atratum Bunge. (2) Cynanchum versicolor Bunge. It provides a detailed description of the botanical features, growth characteristics, and ecological environments of these two species, as well as the characteristics of the herb, its pharmacological actions, medicinal efficacy, and administration guidelines.
Pinyin Name: Bái Wēi
English Name: Blackened Swallowwort Root
Latin Name:Radix Cynanchi Atrati Properties and Flavor: Cold; bitter, salty
Brief Introduction:Radix Cynanchi Atrati is the dried root and rhizome of Cynanchum atratum Bunge. or Cynanchum versicolor Bunge. It is used: (1) to clear heat and cool the blood in febrile conditions associated with consumptive diseases or Yin deficiency; (2) to promote diuresis in heat-induced stranguria and hematuric stranguria; and (3) to detoxify and resolve sores in cases of boils and carbuncles. The herb is commonly known as Blackened Swallowwort Root, Root of Blackened Swallowwort, Root of Versicolored Swallowwort, or Bái Wēi.
Botanical Source:Radix Cynanchi Atrati (Blackened Swallowwort Root) is the dried root and rhizome of Cynanchum atratum Bunge. or Cynanchum versicolor Bunge.—perennial herbs belonging to the genus Cynanchum L., family Apocynaceae (formerly Asclepiadaceae), order Gentianales (formerly Contortae).
Herbal classical texts define Radix Cynanchi Atrati (Blackened Swallowwort Root) as the dried root and rhizome of: (1) Cynanchum atratum Bunge., and (2) Cynanchum versicolor Bunge. These two commonly used species are described below:
(1) Cynanchum atratum Bunge.
Botanical Description:Cynanchum atratum Bunge. is also known as Vincetoxicum atratum (Bunge) Morr. et Decne. Common names include Bai Wei, Blackened Swallowwort, Upright Blackened Swallowwort, Zhi Li Bai Wei, and San Bai Gen. It is a perennial herb reaching 40–70 cm in height. The plant exudes white latex. Rhizomes are short and tufted, bearing numerous slender, fleshy roots over 20 cm long and 2–3 mm in diameter; the outer bark is khaki (yellowish-brown). Stems are erect, green, cylindrical, usually unbranched, and densely covered with ash-gray (grayish-white) short pubescence. Leaves are opposite and shortly stipitate; leaf blades are ovate or ovate-oblong, 5–10 cm long and 3–7 cm wide; the apex is shortly acuminate, the base is rounded, margins are entire; both surfaces are covered with white tomentum—especially dense on the abaxial surface and veins; lateral veins occur in 6–7 pairs.
Inflorescences are many-flowered, densely arranged in umbellate cymes arising from leaf axils near the stem apex; peduncles are absent; flowers are dark purple (moderate purple), ~10 mm in diameter; calyx is green, 5-lobed, externally tomentose, with five small glands at the inner base; corolla is rotate, 5-lobed, externally pubescent with marginal setae (trichomes); catacorolla is 5-lobed, lobes are peltate (shield-shaped) and circular, approximately equal in length to the gynostegium; anther apices bear a circular membranous appendage; each anther locule contains one pendulous, oblong, inflated pollinium; stigma is oblate.
Follicles are solitary, 5–9 cm long and 5–15 mm in diameter; apex is acuminate, base is obtuse, middle portion is dilated. Seeds are numerous, ovoid, narrowly winged, ~4 mm long; coma (seed hair) is white and ~3 cm long. Flowering occurs from May to July; fruiting from August to October.
Ecological Environment: Cynanchum atratum grows on hillsides, mountain slopes, and forest margins.
Growth Characteristics: Cynanchum atratum prefers a warm, humid climate and exhibits moderate cold tolerance. Cultivation is best carried out in sunny, well-drained fields with deep, fertile sandy loam or loam rich in humus.
Characteristics of the Herb: The rhizome of Cynanchum atratum Bunge. is typically curved, thick and short, stubby and knotted, 0.5–1.2 cm in diameter; the upper end bears several circular, concave stem scars or short residual stem bases, while numerous fibrous roots cluster at the lower portion and sides. Roots are cylindrical and slightly curved, resembling a horsetail, 5–25 cm long and 1–2 mm in diameter; the surface is yellowish-brown to brown, with fine longitudinal wrinkles or smooth. The texture is brittle and easily fractured; the fracture surface is flat; cortex is well-developed, yellowish-white to pale yellowish-brown; xylem is small and yellow. Odor is faint; taste is slightly bitter.
Pharmacological Actions: (1) Inhibitory effect on pneumococcus; (2) Clearing heat and promoting diuresis; (3) Enhancing myocardial contractility.
Medicinal Efficacy: Clears heat and nourishes Yin, promotes diuresis and treats stranguria, detoxifies and resolves sores. It is indicated for warm-heat disease, fever with maculae, tidal fever and bone-steaming, lung-heat cough, postpartum emotional distress (postpartum dysphoria), pyretic stranguria, hematuric stranguria, sore throat with swelling and pain, carbuncles and furuncles, pyogenic infections, and snakebite.
Administration of Radix Cynanchi Atrati (Bái Wēi):
Reference:
Administration Guide for Radix Cynanchi Atrati (Bái Wēi)
TCM Books:
(1) Internally: 4.5–9 grams; (2) Internally: water decoction, 1.5–3 qian (approximately 4.5–9 grams), or prepared into pills or powder; (3) Internally: water decoction, 3–15 grams, or prepared into pills or powder.
Contraindications, Precautions, and Adverse Reactions: Radix Cynanchi Atrati should not be combined with Astragalus root, rhubarb root and rhizome, Euphorbia pekinensis, Zingiber rhizome, Lacca sinica exsiccata, Jujube fruit (Fructus Jujubae), or Cornus fruit (Fructus Corni).
(2) Cynanchum versicolor Bunge.
Botanical Description: Cynanchum versicolor Bunge is also known as Vincetoxicum versicolor Decne. It is commonly called Versicolored Swallowwort, Wan Sheng Bai Wei, Wan Bai Wei, or Bai Hua Niu Pi Xiao. This species resembles Cynanchum atratum Bunge, but differs in the following features: it lacks white latex; the upper part of the stems twines, whereas the lower part remains erect; and the leaves are relatively thin in texture. The flowers are small, yellowish-green at anthesis, gradually deepening to dark violet (dull purple), and the inner surface of the corolla lobes is pilose.
Ecological Environment: Cynanchum versicolor Bunge grows in mountainous shrublands.
Characteristics of the Herb: The rhizomes and residual stem bases are slender, and the roots are mostly curved.
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1.Introduction of Bai Wei: Blackened Swallowwort Root
✵The article documents the herb Blackened Swallowwort Root, including its English name, Latin name, Pinyin name, properties and flavor, botanical sources—two plant species: (1) Cynanchum atratum Bunge. (2) Cynanchum versicolor Bunge. It provides a detailed description of the botanical features, growth characteristics, and ecological environments of these two species, as well as the characteristics of the herb, its pharmacological actions, medicinal efficacy, and administration guidelines.
Pinyin Name: Bái Wēi
Herbal classical texts define Radix Cynanchi Atrati (Blackened Swallowwort Root) as the dried root and rhizome of: (1) Cynanchum atratum Bunge., and (2) Cynanchum versicolor Bunge. These two commonly used species are described below:
Botanical Description: Cynanchum atratum Bunge. is also known as Vincetoxicum atratum (Bunge) Morr. et Decne. Common names include Bai Wei, Blackened Swallowwort, Upright Blackened Swallowwort, Zhi Li Bai Wei, and San Bai Gen. It is a perennial herb reaching 40–70 cm in height. The plant exudes white latex. Rhizomes are short and tufted, bearing numerous slender, fleshy roots over 20 cm long and 2–3 mm in diameter; the outer bark is khaki (yellowish-brown). Stems are erect, green, cylindrical, usually unbranched, and densely covered with ash-gray (grayish-white) short pubescence. Leaves are opposite and shortly stipitate; leaf blades are ovate or ovate-oblong, 5–10 cm long and 3–7 cm wide; the apex is shortly acuminate, the base is rounded, margins are entire; both surfaces are covered with white tomentum—especially dense on the abaxial surface and veins; lateral veins occur in 6–7 pairs.
Ecological Environment: Cynanchum atratum grows on hillsides, mountain slopes, and forest margins.
Botanical Description: Cynanchum versicolor Bunge is also known as Vincetoxicum versicolor Decne. It is commonly called Versicolored Swallowwort, Wan Sheng Bai Wei, Wan Bai Wei, or Bai Hua Niu Pi Xiao. This species resembles Cynanchum atratum Bunge, but differs in the following features: it lacks white latex; the upper part of the stems twines, whereas the lower part remains erect; and the leaves are relatively thin in texture. The flowers are small, yellowish-green at anthesis, gradually deepening to dark violet (dull purple), and the inner surface of the corolla lobes is pilose.
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