One of the best known classifications on these lines is that by Warming.1 Warming recognized and defined four ecological classes as follows: Hydrophytes.These live in a watery or wet substratum, with at least 80% of water.
Such terms as hydrophytes, xerophytes, and halophytes had been used by plant geographers before Warmings time e.g., by Schouw;4 and the terms evidently supply a want felt by botanists as they have come into general use.
The criticisms were directed chiefly to the inclusion of sand dune plants among halophytes, to the exclusion of halophytes from xerophytes, to the inclusion of bog xerophytes among hydrophytes, to the inclusion of all conifers among xerophytes and of all deciduous trees among mesophytes, and to the group of mesophytes in general.
Found the most serviceable: - Hydrophytes (submerged aquatic plants) .Plants whose vegetive organs live wholly in water; e.g., most Algae, many mosses, ch as Fontinalis spp., and liverworts, such as Jungermannia spp.; few Pteridophytes, such as Pilularia spp., Isoetes spp.; several wering plants, such as Potamogeton pectinatus, Ceratophyllum p., Hottonia palustris, Utricularia spp., Liltorella lacustris.