Aquatic vegetation may be conveniently classified as follows: Aquatic plants with submerged leaves: Chara spp., Naias spp., Potamogeton pectinatus, Ceratophyllum spp., Myriophyllum spp., Hottonia palustris, Utricularia spp.
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.
The principal other plants which bear the name are the wallflower, Cheiranthus Cheiri, called wall-gillyflower in old books; the dame's violet, Hesperis matronalis, called variously the queen's, the rogue's and the winter gillyflower; the ragged-robin, Lychnis Flos-cuculi, called marsh-gillyflower and cuckoo-gillyflower; the waterviolet, Hottonia palustris, called water-gillyflower; and the thrift, Armeria vulgaris, called sea-gillyflower.
The order is divided into five tribes by characters based on differences in position of the ovules - which are generally semianatropous so that the seed is peltate with the hilum in the centre on one side (or ventral), but sometimes, as in Hottonia and (From Strasburger's Lehrbuch der Botanik.) FIG.