Herba Spirodelae （Spirodela polyrrhiza）Introduction & Source
1. Introduction: It is the whole grass of purple-backed duckweed or duckweed. From June to September each year, the medicine can be obtained by fishing from ponds and lakes.
2. Source: A small herb, floating on the surface of water, having a new bud on the side of the root, attached by a thin stalk before separating from the mother. Roots 5 to 11, fascicular, fibrous, with thin pointed crown and one dimensional tubule.