✵The TCM herbalism is also known as pharmaceutics of Traditional Chinese Medicine, or Chinese pharmaceutics, is the branch of health science dealing with the preparation, dispensing, and proper utilization of Chinese herbs. It is majorly composed of Introduction of Chinese Medicinals, Classification of Chinese Herbs, Formulas, and Patent medicines.
Classifications of Herbs:Pungent-cool Exterior-releasing Herbs.
Introduction: Pungent-cool exterior-releasing herbs: an agent or substance herbs pungent in flavor and cool in property, which is usually used for treating a wind-heat exterior syndrome.
✵Till the date Oct 10th,2019, there are totally  kinds of common TCM herbs,  kinds of related plant species,  kind of insect species, are recorded in this category. These pungent-cool exterior-releasing herbs are briefly introduced separately:
Herba Spirodelae(Common ducksmeat Herb).
Brief Introduction: The herb Herba Spirodelae is the dried entire plant of Spirodela polyrrhiza(L.) Schneid.(family Lemnaceae), used to promote eruption for measles, to relieve itching for urticaria, and to induce diuresis for edema.
✵The herb Herba Spirodelae(Common ducksmeat Herb) is the dried entire plant of Spirodela polyrrhiza(L.) Schneid., it is a plant of the Lemna L. genus, the Lemnaceae family of the Arales order. It is also known as Herba Spirodelae, Common ducksmeat Herb, Fú Pínɡ.
Common official herbal classics and other famous herbal classics defined the herb Herba Spirodelae(Common ducksmeat Herb) as the dried entire plant of :(1). Spirodela polyrrhiza(L.) Schneid., or (2).Lemna minor L. These 2 commonly used species are introduced as:
(1).Spirodela polyrrhiza(L.)Schneid.: It is also known as purple duckweed, perennial small herb, floating on the surface. Roots 5~11 fascicles, slender, fibrous, 3~5 cm long. New shoots are produced on one side of the root's shoot, which is connected to the parent by a thin stalk before it separates. Leaves flat, solitary or 2~5 clustered, broadly obovate, 4~10 mm long, 4~6 mm wide, apex obtuse, slightly concave at above part, dark green, purplish at bottom part, palmate veins 5~11 inconspicuous. Inflorescence grow within the margin of leaf body; Flowers and plants, male and female with forest; Bud pouch, short, 2-lipped, with 2 male flowers and 1 female flower, without perianth; Male flower has 2 stamens, anther 2 rooms, filaments fine; 1 female flower's pistil, ovary sessile, 1 locule, 2 ovules erect, style short, stigma flattened or annular. Fruit round, the margin has a wing. Its flowering period is from April to June, fruiting from May to July.
Ecological environment: the plant grows in other marshes, paddy fields, bays or still waters. It is widely distributed in the north and south of China.
(2).Lemna minor L.: It is also known as duckweed, small floating herbs. 1 root, 3~4 cm long, slender, root sheath wingless, root crown obtuse or truncated. Leaves symmetrical, obovate, elliptic or subcircular, 1.5~6 mm long, 2~3 mm wide, smooth above, green, opaque, yellow or purple below, full-line, with inconspicuous 3 veined veins. The leaf has a capsule on the backside, and the new leaf emerges from the capsule, joining the parent with a very short stalk, and then falling off. Flowers unisexual, hermaphroditic, grow at lobulated edges; Bud winglike, with 1 female flower, 2 male flowers; Male anthers 2-loculed, filaments slender; Female flowers with 1 pistil, ovary giant, 1 ovule curved. Fruit subgyro, wingless. 1 seed, with raised endosperm and 12~15 irregular convex veins.
Ecological environment: the plant grows in ponds, paddy fields, lakes or still water and often mixes with purple duckweed. It is distributed throughout China from north to south area.
Trait Identification: lobulates are ovoid, ovoid or ovoid ellipsoid, 3~6 mm in diameter. Single scattered or 2~5 pieces of the collection, the upper surface is light green to grayish-green, the lower surface is green to purple-brown, edge neat or slightly roll, the upper surface on both sides of a small depression, the lower surface of several roots. Light and fragile. Slight smell, mild taste. The herb color green, back purple is the best.