✵The article documents the herb Eucommia Bark—its English name, Latin name, Pinyin name, properties and flavors, botanical source—a single plant species, Eucommia ulmoides Oliv., and provides a detailed description of the botanical features, growth characteristics, and ecological environment of this species; as well as the characteristics of the herb, its pharmacological actions, medicinal efficacy, and administration guidelines.
Cortex Eucommiae (Eucommia Bark)
Pinyin Name: Dù Zhònɡ
English Name: Eucommia Bark
Latin Name:Cortex Eucommiae Properties and Flavors: Warm in nature; sweet in taste.
Brief Introduction:Cortex Eucommiae is the dried stem bark of Eucommia ulmoides Oliv. It is used to tonify the liver and kidneys, strengthen tendons and bones, and stabilize pregnancy—indicated for soreness and pain in the lumbar region and knees, impotence, frequent urination, threatened abortion, and, in modern practice, hypertension. The herb is commonly known as Cortex Eucommiae, Eucommia Bark, or Dù Zhòng.
Botanical Source: Classical herbal works define Eucommia Bark (Dù Zhòng) as the dried bark (cortex) of Eucommia ulmoides Oliv., a species belonging to the family Eucommiaceae. It is the sole extant species of the genus Eucommia, order Garryales (formerly in Eucommiales). This medicinally important species is described below:
(1) Eucommia ulmoides Oliv.
Botanical Description: A deciduous tree commonly known as Dù Zhòng, native to China. Mature trees reach up to 20 m in height, with trunk diameters of approximately 50 cm.
The bark is taupe (grayish-brown), coarse and rough, and when broken, reveals numerous fine, silvery-white, elastic rubber threads. Young shoots are covered with brown pubescence, becoming glabrescent with age; older branches bear conspicuous lenticels. Buds are ovoid, glossy, reddish-brown, subtended by 6–8 imbricate scales with ciliate margins.
Leaves are simple and alternate; petioles measure 1–2 cm long and bear longitudinal grooves on the upper surface, sparsely covered with long, soft hairs. Leaf blades are elliptic, ovate (egg-shaped), or oblong, thinly coriaceous, 6–15 cm long and 3.5–6.5 cm wide; the apex is acuminate, and the base is rounded or broadly cuneate. The upper surface is dark green (sap green), initially pubescent with brown hairs, later becoming glabrescent; the lower surface is pale green (pea green), slightly wrinkled in mature leaves, with serrated margins and 6–9 pairs of prominent lateral veins.
Flowers are unisexual and dioecious, grow on the current year’s branchlets near the base. Male flowers are achlamydeous (lacking perianth); pedicels are ~3 mm long and glabrous; bracts are obovate-spatulate, 6–8 mm long, with rounded apices and ciliate margins; they are caducous. Stamens are ~1 cm long, glabrous, and lack a pistillode. Female flowers are solitary; bracts are obovate; pedicels are 8 mm long; the ovary is glabrous, unilocular, flattened and elongated, with a bilobed apex; the gynophore (podogynium) is extremely short; no staminodes are present.
The fruit is a samara: flattened, oblong-ovate, 3–3.5 cm long and 1–1.3 cm wide; the apex is bilobed, the base is cuneate, and thin membranous wings surround the central nut.
The nut is centrally located, slightly raised, and 2–3 mm long, with distinct nodes and articulations at the junction with the carpopodium (fruit stalk). Seeds are flat and linear, 1.4–1.5 cm long and 3 mm wide, rounded at both ends. Flowering occurs in early spring; fruits mature in autumn.
Characteristics of the Herb: The bark occurs as flat plates, rolled pieces (with both edges slightly incurved), or irregular fragments, varying in size; thickness ranges from 2–7 mm (commonly 3–7 mm). The outer surface is light grayish-brown or taupe, smooth to coarsely textured, bearing conspicuous longitudinal wrinkles or irregular longitudinal fissures; some pieces retain a thin outer layer, while others exhibit a thicker, rougher periderm—often appearing obliquely square with transverse fissure lenticels; light gray lichen spots may be present. The inner surface is dark purplish-brown or reddish-brown and smooth. The texture is brittle and fractures easily; the fracture surface is coarse and uneven, densely connected by fine, silvery-white, highly elastic rubber threads. The herb has a faint odor and a slightly bitter taste; a gelatinous residue remains upon chewing.
Ecological Environment: The tree grows at elevations of 300–500 m above sea level—in low hills and mountains, valleys, open forests, or gentle woodland slopes. Native to China, it is widely distributed and extensively cultivated throughout the country.
Growth Characteristics: The tree prefers a warm, moist climate and a sunny environment, and it can withstand cold. The tree can survive at low temperatures of -30 °C (Celsius, or -22 °F); the average annual air temperature in its natural distribution range is 13–17 °C (55.4–62.6 °F), and annual precipitation is 500–1,500 mm. It is advisable to select sites with ample sunlight, deep soil layers, and humus-rich sandy loam or clay loam for cultivation. In general, the tree is highly adaptable and has no strict soil requirements; it can grow on infertile laterite or rocky cliffs.
The growth rate of Eucommia trees is relatively slow in the early stage, with rapid growth occurring between ages 7 and 20 years. After age 20, the growth rate declines annually. After age 50, height growth ceases, and the tree eventually withers naturally.
To date, up to 14 species of Eucommia have been identified worldwide, all of which subsequently became extinct on the continents of Asia and Europe. The Eucommia native to China is the sole surviving relict species of the family Eucommiaceae and genus Eucommia.
Medicinal Efficacy: Tonifies the liver and kidney, strengthens the bones and tendons, and stabilizes pregnancy. Indicated for liver-kidney deficiency, soreness and pain in the lumbar region and knees, flaccidity and weakness of the lower limbs, debility of tendons and bones, impotence (asynodia, impotentia), frequent urination, dribbling urination, genital damp-itching (damp and itching at the genital region), rheumatic arthralgia, dizziness and blurred vision, threatened abortion, habitual abortion, and hypertension (high blood pressure).
Administration of Cortex Eucommiae (Dù Zhònɡ):
Reference:
Administration Guide for Cortex Eucommiae (Dù Zhònɡ)
TCM Books:
(1) Internally: 6–10 grams; (2) Internally: water decoction, 3–5 qián (≈9–15 grams); infused in wine; or prepared as pills or powder; (3) Internally: water decoction, 6–15 grams; or infused in wine; or prepared as pills or powder.
Contraindications, Precautions, and Adverse Reactions: Cortex Eucommiae should not be combined with Snakeskin (Pellis Serpentis) or Scrophularia root (Radix Scrophulariae).
✵The article documents the herb Eucommia Bark—its English name, Latin name, Pinyin name, properties and flavors, botanical source—a single plant species, Eucommia ulmoides Oliv., and provides a detailed description of the botanical features, growth characteristics, and ecological environment of this species; as well as the characteristics of the herb, its pharmacological actions, medicinal efficacy, and administration guidelines.
Pinyin Name: Dù Zhònɡ
Botanical Description: A deciduous tree commonly known as Dù Zhòng, native to China. Mature trees reach up to 20 m in height, with trunk diameters of approximately 50 cm.
Flowers are unisexual and dioecious, grow on the current year’s branchlets near the base. Male flowers are achlamydeous (lacking perianth); pedicels are ~3 mm long and glabrous; bracts are obovate-spatulate, 6–8 mm long, with rounded apices and ciliate margins; they are caducous. Stamens are ~1 cm long, glabrous, and lack a pistillode. Female flowers are solitary; bracts are obovate; pedicels are 8 mm long; the ovary is glabrous, unilocular, flattened and elongated, with a bilobed apex; the gynophore (podogynium) is extremely short; no staminodes are present.
The fruit is a samara: flattened, oblong-ovate, 3–3.5 cm long and 1–1.3 cm wide; the apex is bilobed, the base is cuneate, and thin membranous wings surround the central nut.
Characteristics of the Herb: The bark occurs as flat plates, rolled pieces (with both edges slightly incurved), or irregular fragments, varying in size; thickness ranges from 2–7 mm (commonly 3–7 mm). The outer surface is light grayish-brown or taupe, smooth to coarsely textured, bearing conspicuous longitudinal wrinkles or irregular longitudinal fissures; some pieces retain a thin outer layer, while others exhibit a thicker, rougher periderm—often appearing obliquely square with transverse fissure lenticels; light gray lichen spots may be present. The inner surface is dark purplish-brown or reddish-brown and smooth. The texture is brittle and fractures easily; the fracture surface is coarse and uneven, densely connected by fine, silvery-white, highly elastic rubber threads. The herb has a faint odor and a slightly bitter taste; a gelatinous residue remains upon chewing.
Ecological Environment: The tree grows at elevations of 300–500 m above sea level—in low hills and mountains, valleys, open forests, or gentle woodland slopes. Native to China, it is widely distributed and extensively cultivated throughout the country.
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