✵The article records the herb Chuanlong Yam—its English name, Latin name, Pinyin name, properties and flavor, and botanical source: (1) Dioscorea nipponica Makino and (2) Dioscorea nipponica Makino subsp. rosthornii (Prain et Burkill) C. T. Ting—with a detailed introduction to the botanical features, growth characteristics, and ecological environments of these two species; the macroscopic and microscopic characteristics of the herb Chuanlong Yam; its pharmacological actions, medicinal efficacy, and administration guidelines.
Rhizoma Dioscoreae Nipponicae (Chuan Di Long)
Pinyin Name: Chuān Shān Lónɡ (also written as Chuān Dì Lónɡ)
English Name: Chuanlong Yam
Latin Name:Rhizoma Dioscoreae Nipponicae Property and Flavor: Neutral; bitter
Brief Introduction:Rhizoma Dioscoreae Nipponicae is the dried rhizome of Dioscorea nipponica Makino, used to dispel wind-dampness, activate blood circulation, unblock collateral meridians, and resolve phlegm. It is indicated for rheumatoid arthralgia, sprains, traumatic pain, and chronic cough with sputum. The herb is commonly known as Chuan Shan Long or Chuān Shān Lónɡ.
Botanical Source: Classical herbal works define Rhizoma Dioscoreae Nipponicae (Chuan Shan Long) as the dried rhizome of (1) Dioscorea nipponica Makino. Other authoritative herbal classics include either (1) Dioscorea nipponica Makino or (2) Dioscorea nipponica Makino subsp. rosthornii (Prain et Burkill) C. T. Ting. Both belong to the genus Dioscorea, family Dioscoreaceae (yam family), order Dioscoreales. These two commonly used species are described below:
(1) Dioscorea nipponica Makino
Botanical Description:Dioscorea nipponica Makino is commonly known as Chuān Lóng Shǔ Yù. It is a perennial twining vine, reaching up to 5 meters in length. Rhizomes are amphitropous, cylindrical, woody, and highly branched; the cork layer is conspicuously exfoliating. Stems are sinistral, cylindrical, and nearly glabrous. Leaves are alternate and simple; petioles measure 10–20 cm; leaf blades are palmately cordate, highly variable in size—basal leaves on the stem are 10–15 cm long and 9–13 cm wide, with an unevenly triangular-lobed, moderately lobed, or deeply parted margin; apical leaves are smaller and nearly entire. The upper surface is yellowish-green, glossy, and glabrous or sparsely covered with fine white pubescence—especially dense along the veins.
Flowers are unisexual and dioecious. Male inflorescences are axillary spikes; the base typically bears umbellules comprising 2–4 flowers, while the apex usually bears a single flower. Bracts are lanceolate, acuminate at the apex, and shorter than the perianth. The perianth is phialiform (disc-shaped), 6-lobed, with obtuse lobe apices. There are six stamens, inserted at the center of each perianth lobe; anthers are introrse. Female inflorescences are spicate and solitary; the perianth is 6-lobed, with lanceolate lobes; the stigma is trifurcate, and each lobe is bifurcated again.
Fruits are capsule-like, dull yellow at maturity, prismatic, with a concave apex and orbicular base; each ridge bears an aliform (wing-like) extension. Fruits vary in size, typically ~2 cm long and ~1.5 cm wide. Each locule contains two seeds; occasionally only one seed is fertile. Seeds are inverted at the base of the funicle, with unequal membranous wings surrounding them—the upper portion is rectangular, approximately twice as long as wide. Flowering occurs from June to August; fruiting, from August to October.
Ecological Environment: The plant grows on hillsides and mountain slopes, forest margins, both banks of stream valleys, and shrublands, at elevations of 300–2,000 meters above sea level.
Growth Characteristics:Dioscorea nipponica exhibits broad environmental adaptability and grows within a temperature range of 8–35 °C (46–95 °F); optimal growth occurs at 15–25 °C (59–77 °F). It is drought-tolerant, and plants require light exposure from the late seedling stage through maturity. Cultivation is best carried out in loose, fertile sandy loam soil; loam and clay loam soils are also suitable.
Characteristics of the Herb: The rhizome is cylindrical to slightly curved and branched, 10–15 cm long and 0.3–1.5 cm in diameter. The surface is yellowish-white or brownish-yellow, bearing irregular longitudinal grooves, punctate root scars, and protruding stem scars on one side; occasionally, remnants of membranous, light brown cortex and fine roots persist. The texture is hard; the fracture surface is flat, white or yellowish-white, with scattered light brown vascular bundles. The herb has a faint odor and a bitter, astringent taste.
Pharmacological Actions: (1) antitussive, expectorant, antiasthmatic, anti-hypoxic, inhibits platelet aggregation, diuretic, antibacterial, and antiviral activities; (2) aqueous decoction suppresses both cellular and humoral immunity while enhancing the phagocytic function of phagocytes; (3) significantly reduces serum cholesterol levels and blood pressure, slows heart rate, and improves coronary circulation.
Medicinal Efficacy: Promotes blood circulation and relaxes tendons and channels; invigorates blood flow to unblock meridian obstructions; aids digestion and alleviates water retention; dispels wind and eliminates dampness; resolves phlegm; prevents malarial attacks or recurrence; and relieves cough. It is indicated for wind-cold-damp bi syndrome (anemofrigid-damp arthralgia), limb numbness, chronic bronchitis, chest obstruction and cardiodynia (angina pectoris), dyspepsia (indigestion), traumatic injuries from falls, malaria, and carbuncles.
Administration of Rhizoma Dioscoreae Nipponicae (Chuān Dì Lónɡ):
Reference:
Administration Guide for Rhizoma Dioscoreae Nipponicae (Chuān Dì Lónɡ)
TCM Books:
(1) Internally:water decoction, 0.5–1 liang (≈15–30 grams); fresh herb, 1–2 liang (≈30–60 grams); or wine-based infusion. External use: crush fresh herb and apply as a poultice. (2) Internally:water decoction, dried herb 6–9 grams, fresh herb 30–45 grams, or wine-based infusion. External use: appropriate amount; crush fresh herb and apply as a poultice.
(2) Dioscorea nipponica Makino subsp. rosthornii (Prain et Burkill) C. T. Ting
Botanical Description:Dioscorea nipponica Makino subsp. rosthornii (Prain et Burkill) C. T. Ting—commonly known as Chái Huáng Jiāng—is a subspecies of Dioscorea nipponica Makino. Key distinguishing features include: a robust and stout plant habit; rhizomes lacking exfoliating cork; flowers usually pedicellate; and leaf blades bearing more setae. Flowering occurs from June to August; fruiting, from August to October.
Ecological Environment: Grows in valley shrublands, sparse mixed-wood forests, and forest margins at elevations of 1,000–1,800 m above sea level.
Characters of herbs: The rhizome resembles that of Dioscorea nipponica Makino, but is thicker, has a smoother surface, and lacks deciduous corky bark.
✵The article records the herb Chuanlong Yam—its English name, Latin name, Pinyin name, properties and flavor, and botanical source: (1) Dioscorea nipponica Makino and (2) Dioscorea nipponica Makino subsp. rosthornii (Prain et Burkill) C. T. Ting—with a detailed introduction to the botanical features, growth characteristics, and ecological environments of these two species; the macroscopic and microscopic characteristics of the herb Chuanlong Yam; its pharmacological actions, medicinal efficacy, and administration guidelines.
Pinyin Name: Chuān Shān Lónɡ (also written as Chuān Dì Lónɡ)
Botanical Description: Dioscorea nipponica Makino is commonly known as Chuān Lóng Shǔ Yù. It is a perennial twining vine, reaching up to 5 meters in length. Rhizomes are amphitropous, cylindrical, woody, and highly branched; the cork layer is conspicuously exfoliating. Stems are sinistral, cylindrical, and nearly glabrous. Leaves are alternate and simple; petioles measure 10–20 cm; leaf blades are palmately cordate, highly variable in size—basal leaves on the stem are 10–15 cm long and 9–13 cm wide, with an unevenly triangular-lobed, moderately lobed, or deeply parted margin; apical leaves are smaller and nearly entire. The upper surface is yellowish-green, glossy, and glabrous or sparsely covered with fine white pubescence—especially dense along the veins.
Flowers are unisexual and dioecious. Male inflorescences are axillary spikes; the base typically bears umbellules comprising 2–4 flowers, while the apex usually bears a single flower. Bracts are lanceolate, acuminate at the apex, and shorter than the perianth. The perianth is phialiform (disc-shaped), 6-lobed, with obtuse lobe apices. There are six stamens, inserted at the center of each perianth lobe; anthers are introrse. Female inflorescences are spicate and solitary; the perianth is 6-lobed, with lanceolate lobes; the stigma is trifurcate, and each lobe is bifurcated again.
Ecological Environment: The plant grows on hillsides and mountain slopes, forest margins, both banks of stream valleys, and shrublands, at elevations of 300–2,000 meters above sea level.
Characteristics of the Herb: The rhizome is cylindrical to slightly curved and branched, 10–15 cm long and 0.3–1.5 cm in diameter. The surface is yellowish-white or brownish-yellow, bearing irregular longitudinal grooves, punctate root scars, and protruding stem scars on one side; occasionally, remnants of membranous, light brown cortex and fine roots persist. The texture is hard; the fracture surface is flat, white or yellowish-white, with scattered light brown vascular bundles. The herb has a faint odor and a bitter, astringent taste.
Botanical Description: Dioscorea nipponica Makino subsp. rosthornii (Prain et Burkill) C. T. Ting—commonly known as Chái Huáng Jiāng—is a subspecies of Dioscorea nipponica Makino. Key distinguishing features include: a robust and stout plant habit; rhizomes lacking exfoliating cork; flowers usually pedicellate; and leaf blades bearing more setae. Flowering occurs from June to August; fruiting, from August to October.
Ecological Environment: Grows in valley shrublands, sparse mixed-wood forests, and forest margins at elevations of 1,000–1,800 m above sea level.
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