Reed (scientific name: Phragmites Australia (CAV.) Trin. Ex Steud.) is a tall grass that has been aquatic or wet for many years, and its rhizomes are very developed. The culm is erect, with a height of 1-3 meters and more than 20 nodes. The lower part of leaf sheath is shorter than its upper part and longer than its internodes; A circle of short fiber hairs about 1 mm is densely planted at the edge of the ligule, which is easy to fall off; Leaf blade is needle-linear, hairless, and the top end is long and tapering into a silk shape. Panicle is large with many branches; Spikelets glabrous; The two ridges of palea are rough; Anthers yellow; Caryophyll is about 1.5 mm long.