• Scientific Name: Egeria densa Planchon
• Ref: Ann. Sci. Nat., Bot., sér. 3. 11: 80. 1849.
• Synonyms: Anacharis densa (Planchon) Victorin; Elodea densa (Planchon) Caspary; Philotria densa (Planchon) Small.
• English Common Name: Brazilian waterweed
• Chinese Common Name: 水蕴草 shui yun cao
• Family: Hydrocharitaceae
• Genus: Egeria
• Distribution: Known from a cultivated fish pond. Guangdong [native to South America].
• Photo: 05/17/2020, Hangzhou, Zhejiang

 Stems 1-3 mm diam. Leaves whorled, recurved, 10-40 × 1.5-4.5 mm, margin minutely serrate. Male spathes 2-4-flowered, 7.5-12 mm; pedicel to 8 cm. 2n = 46.(Flora of China)