4-25 Zannichelliaceae, horned pondweed family

Abstract

All aquatic plants, they frequent fresh or brackish waters. A small family, there are only four genera. A single species reaches North America including Nova Scotia. Typically, they have submerged unisexual flowers, arising from the leaf axils. Perianths are absent or reduced to three minute tepals. Stamens are solitary; ovaries 1-9. The fruits are achenes bearing persistent styles. Leaves opposite or whorled, scalelike or linear, with a single vein. The stems are dimorphic, upper ones are leafy while the lower ones are stoloniferous. Image use given by Roger Lloyd and David Mazerolle.