Abstract:

Aquatic flowering plants belong to the superphylum Spermatophyta and the phylum Magnoliophyta, characterized by possession of true roots, stems, and leaves, and production of seeds from flowers. The phylum contains most of the conspicuous land plants of the world. Aquatic flowering plants are almost exclusively fresh-water inhabitants. Test procedures are described for duckweed (Section 8211), which floats on the surface of the water, and aquatic emergent plants (Section 8220), which have roots extending into the sediment.