✵The article records the herb Coral-bean Bark, including its English name, Latin name, Pinyin name, properties and flavor, botanical sources—two plant species: (1) Erythrina variegata L. var. orientalis (L.) Merr. and (2) Erythrina arborescens Roxb.—along with detailed descriptions of the botanical features, growth characteristics, and ecological environments of these two species; the macroscopic and microscopic characteristics of the herb Coral-bean Bark; its pharmacological actions, medicinal efficacy, and administration guidelines.
Cortex Erythrinae (Coral-bean Bark)
Pinyin Name: Hǎi Tóng Pí
English Name: Coral-bean Bark
Latin Name:Cortex Erythrinae Properties and Flavor: Neutral in nature; pungent and bitter.
Brief Introduction:Cortex Erythrinae is the dried bark of Erythrina variegata L. var. orientalis (L.) Merr. or Erythrina arborescens Roxb., used to dispel wind-dampness, unblock the collateral meridians, and relieve itching in cases of rheumatoid arthritis; it is also applied externally for neurodermatitis and chronic eczema. It is commonly known as Cortex Erythrinae, Coral-bean Bark, or Hǎi Tóng Pí.
Botanical Source: Classical herbal works define Cortex Erythrinae (Coral-bean Bark) as the dried bark of (1) Erythrina variegata L. var. orientalis (L.) Merr. or (2) Erythrina arborescens Roxb.—both belonging to the genus Erythrina, family Fabaceae (Leguminosae, the legume or pea family), order Rosales. These two commonly used species are described below:
(1) Erythrina variegata L. var. orientalis (L.) Merr.
Botanical Description:Erythrina variegata L. var. orientalis (L.) Merr., also known as Erythrina indica Lam., is commonly called Cì Tóng. It is a large tree reaching up to 20 meters in height. The bark is taupe-brown (grayish brown); branches are primrose-yellow (pale yellow) to khaki, densely gray-tomentose, bearing black conical spines that shed off within two or three years. Leaves are alternate or clustered at branch tips; stipules (peraphylla) are linear, 1–1.3 cm long, and caducous; leaves are trifoliolate; leaflets are broadly ovate to orthorhombic-ovate, 10–15 cm long; the apical leaflet is longer than wide; the apex is acuminate to obtuse; the base is subtruncated or broadly rhombic; veins on both surfaces bear sparse trichomes.
Racemes are 15 cm long and tomentose; peduncles are 7–10 cm long; the calyx is spathe-like, 2–3 cm long, with an obliquely split mouth, dehiscing from the back to the base; the corolla is papilionaceous, bright red; the vexillum is 5–6 cm long; the alae and keel petals (carina) are nearly equal in length and shorter than the calyx; there are 10 stamens, diadelphous; filaments are mauve (lilac), 3–3.5 cm long; anthers are yellow; there is 1 style, pea-green (pale green), with an undivided stigma densely covered with purple pubescence.
Pods (legumes) are bead-like and slightly curved; seeds number 1–8, are spheroidal (globular), and dark-red (dull red). Flowering occurs in March.
Ecological Environment: The tree grows wild in open fields or is cultivated as a street tree.
Growth Characteristics:Erythrina variegata prefers a warm, moist climate and full sun; it is not cold-tolerant. It thrives in regions where the annual mean temperature is 20.1 °C (68.18 °F), the mean January temperature exceeds 8 °C (46.4 °F), and annual precipitation exceeds 1,110 mm. Soil requirements are not strict, but well-drained sandy loam is optimal.
Characteristics of the Herb: The bark is semi-cylindrical or platy, with both sides slightly curled; it is approximately 40 cm long and 0.25–1.5 cm thick. The outer surface is yellow-brown to brownish-black and often bears longitudinal grooves of varying widths. The cork layer of old bark is thick and sometimes scraped off; the exposed cork surface is rough and bears yellow lenticels, with scattered nail-shaped thorns (spikes) or circular scars where thorns have been removed. The thorns are long-conical, 5–8 mm high, sharply pointed at the apex, and 5–10 mm in diameter at the base. The inner surface is yellow-brown, relatively flat, and marked with fine longitudinal reticulate patterns. Root bark lacks thorns. The herb is tough and tensile, easily splitting longitudinally but difficult to break; the fracture surface is light brown and flaky. It has a faint odor and a slightly bitter taste.
Pharmacological Actions: (1) In vitro antifungal activity against dermatophytes, including Trichophyton violaceum, Microsporum schoenleinii, Trichophyton rubrum, and Epidermophyton floccosum; (2) In vitro antibacterial activity against Staphylococcus aureus.
Medicinal efficacy: Disperses wind-dampness, activates the tendons and collaterals, expels parasites, and alleviates pruritus. It is indicated for wind-damp bi syndrome manifesting as limb numbness and pain, rheumatic arthralgia, muscular spasm, lumbago and leg pain, traumatic injuries (e.g., contusions or sprains), dysentery, and dental pain. Topically, it is used to treat refractory dermatoses—including neurodermatitis, scabies, and chronic eczema.
Administration of Cortex Erythrinae (Hǎi Tónɡ Pí):
Reference:
Administration Guide of Cortex Erythrinae (Hǎi Tónɡ Pí)
TCM Books:
(1) Internally:water decoction, 2–4 qian (about 6–12 grams), or prepared as a medicinal wine infusion; externally: fumigation wash with decoction, or application of finely powdered herb; (2) Internally:water decoction, 6–12 grams, or prepared as a medicinal wine infusion; externally: appropriate amount for fumigation wash with decoction, topical application of wine-based extract, or application of finely powdered herb.
(2) Erythrina arborescens Roxb.
Botanical Description:Erythrina arborescens Roxb.—also known as Erythrina tienensis Wang et Tang—is commonly referred to as Qiáo Mù Cì Tóng. It is a tree reaching 7–8 m in height. The bark bears conical spines. Leaves are trifoliolate; leaflets are oblate, 10–20 cm long and 8–19 cm wide; the apex is acute; the base is subtruncated; both surfaces are glabrous; petiolules are stout.
Racemes are axillary; flowers are densely arranged on the upper portion of the peduncle; the rachis and pedicels are glabrous; the calyx is bilabiate and glabrous; the corolla is scarlet, up to 4 cm long; the alae are short—approximately one-quarter the length of the vexillum; the keel petals (carina) are rhombic, longer than the alae, and lack claws; there are 10 stamens, 5 long and 5 short; the ovary is stipitate and pubescent with yellow trichomes.
Pods (legumes) are fusiform (spindle-shaped), slightly curved, with pointed apices and bases; the apex is rostrate (beaked); the base is stipitate; they measure approximately 10 cm in length and 1.2 cm in width.
Ecological Environment: The plant grows in gullies or on grassy slopes.
Characteristics of the Herb: The bark of Erythrina arborescens Roxb. closely resembles that of Erythrina variegata L. var. orientalis (L.) Merr.: it occurs as inwardly curled transverse strips or small flat quadrangular pieces, 3–6 mm thick; the outer surface is yellowish-brown to tan (chocolate brown) or brownish-black; occasionally, it appears sap-green (dark green); the surface is coarse and rough; the cork layer is often exfoliated, rendering the boundary between thorn bases and residual cork indistinct; the inner surface is light yellowish-brown, smooth, and marked by fine longitudinal striations; the texture is firm and hard; the fracture surface is yellow and fibrous; the herb has a faint odor and a mildly bitter taste.
✵The article records the herb Coral-bean Bark, including its English name, Latin name, Pinyin name, properties and flavor, botanical sources—two plant species: (1) Erythrina variegata L. var. orientalis (L.) Merr. and (2) Erythrina arborescens Roxb.—along with detailed descriptions of the botanical features, growth characteristics, and ecological environments of these two species; the macroscopic and microscopic characteristics of the herb Coral-bean Bark; its pharmacological actions, medicinal efficacy, and administration guidelines.
Pinyin Name: Hǎi Tóng Pí
Botanical Description: Erythrina variegata L. var. orientalis (L.) Merr., also known as Erythrina indica Lam., is commonly called Cì Tóng. It is a large tree reaching up to 20 meters in height. The bark is taupe-brown (grayish brown); branches are primrose-yellow (pale yellow) to khaki, densely gray-tomentose, bearing black conical spines that shed off within two or three years. Leaves are alternate or clustered at branch tips; stipules (peraphylla) are linear, 1–1.3 cm long, and caducous; leaves are trifoliolate; leaflets are broadly ovate to orthorhombic-ovate, 10–15 cm long; the apical leaflet is longer than wide; the apex is acuminate to obtuse; the base is subtruncated or broadly rhombic; veins on both surfaces bear sparse trichomes.
Racemes are 15 cm long and tomentose; peduncles are 7–10 cm long; the calyx is spathe-like, 2–3 cm long, with an obliquely split mouth, dehiscing from the back to the base; the corolla is papilionaceous, bright red; the vexillum is 5–6 cm long; the alae and keel petals (carina) are nearly equal in length and shorter than the calyx; there are 10 stamens, diadelphous; filaments are mauve (lilac), 3–3.5 cm long; anthers are yellow; there is 1 style, pea-green (pale green), with an undivided stigma densely covered with purple pubescence.
Ecological Environment: The tree grows wild in open fields or is cultivated as a street tree.
Characteristics of the Herb: The bark is semi-cylindrical or platy, with both sides slightly curled; it is approximately 40 cm long and 0.25–1.5 cm thick. The outer surface is yellow-brown to brownish-black and often bears longitudinal grooves of varying widths. The cork layer of old bark is thick and sometimes scraped off; the exposed cork surface is rough and bears yellow lenticels, with scattered nail-shaped thorns (spikes) or circular scars where thorns have been removed. The thorns are long-conical, 5–8 mm high, sharply pointed at the apex, and 5–10 mm in diameter at the base. The inner surface is yellow-brown, relatively flat, and marked with fine longitudinal reticulate patterns. Root bark lacks thorns. The herb is tough and tensile, easily splitting longitudinally but difficult to break; the fracture surface is light brown and flaky. It has a faint odor and a slightly bitter taste.
Botanical Description: Erythrina arborescens Roxb.—also known as Erythrina tienensis Wang et Tang—is commonly referred to as Qiáo Mù Cì Tóng. It is a tree reaching 7–8 m in height. The bark bears conical spines. Leaves are trifoliolate; leaflets are oblate, 10–20 cm long and 8–19 cm wide; the apex is acute; the base is subtruncated; both surfaces are glabrous; petiolules are stout.
Ecological Environment: The plant grows in gullies or on grassy slopes.
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