Duckweed (Leaves are flat and nearly round, light green on top and purple on the back, with slightly curled edges. The underside has many fibrous roots and a soft texture.)
Large Duckweed
【Naming】
n 【Source】n
Classified as “medium grade” in the Classic of Herbal Medicine
n 【Frequency of Use】n
E
n 【Botanical Origin】n
The dried whole plant of Spirodela polyrrhiza (L.) Schleid. of the duckweed family (Lemnaceae). In Taiwan, the medicinal material used is more commonly Lemna minor L. (common duckweed).
n 【Characteristics】n
The thallus is flat and nearly circular, about 4~6㎜ in diameter, growing alone or in clusters. The upper surface is yellowish-green, relatively smooth, and the edges are slightly curled upward. The lower surface is dark brown to purplish-black, slightly raised, with many fibrous roots on one side. The texture is soft, and the taste is slightly fishy.nLemna minor and Spirodela polyrrhiza are similar in shape, but both the upper and lower surfaces of Lemna minor are green or gray-green, and the lower surface has only one thin root.
n 【Identification】n
“The ones with purple backs are superior.” (Essentials of Materia Medica). “One kind has a green surface and a purple-red back like blood, called purple-backed duckweed, which is good for medicinal use.” (Easy Readings of Materia Medica).nThe best ones are individually neat and clean, with a purple back and no weeds. Black and yellow ones are second-rate.
n 【Category】n
Whole Herb