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CommentsThis common pondweed has a rather grassy appearance. It can be difficult to distinguish Leafy Pondweed (Potamogeton foliosus) from other submerged pondweeds (Potamogeton spp.) with linear leaves unless the floral spikes are present. Compared to these species, the floral spikes of Leafy Pondweed are very short and densely flowered, and they have shorter peduncles (3-12 mm.). In addition, the leaves of Leafy Pondweed usually lack visible glands and its stems are flattened, rather than terete. The achenes of this pondweed are also distinctive because of their winged crested keels, which are visible to the naked eye. Different varieties of Leafy Pondweed have been described across its geographic range, although they tend to intergrade. In Illinois, it is the typical variety (Potamogeton foliosus foliosus) that is commonly encountered.