azolla microphylla, azolla nilotica or azolla anabaena or water fern or azolla filiculoides or water lettuce ,stemless water plant

aquatic plant azolla anabaena filiculoides microphylla nilotica cold combretaceae cool dew drop duckweed fall falling rain genus lemna glaucifoloa craib hydrophyte hydrophytic lemma minor lemnaceae lesser perpusilla pistia stratiotes polyrrhiza pond droplet rainy day season river schleid seasonal spirodela oligorrhiza stemless water terminalia fern lettuce wet