131964 HORNED PONDWEED Zannichellia palustris (Zannichelliaceae) Aquatic. Slender and submerged perennial that grows in still or slow-flowing fresh, or slightly brackish, water. FLOWERS are minute, greenish and borne in short-stalked clusters in leaf axils (May-Aug). FRUITS have a slender beak. LEAVES are 1.5mm wide and up to 5cm long, pointed and translucent. STATUS-Widespread throughout, but local.