Invasive

Curly-leaf pondweed (Potamogeton crispus) Description:  Curly-leaf pondweed has underwater leaves only.  Mature stems may be several meters in length. The leaves of this plant are key to its identification.  When visible, (they disintegrate early in the plant’s growth cycle) are slightly joined to the stem at the leaf base and 4 to . . .

Variable water-milfoil (Myriophyllum heterophyllum) Description:  Variable water-milfoil is an underwater, plant with branching stems rising out from above the surface with compact, spreading roots. Habitat:  Variable water-milfoil is an extremely well adapted plant, able to thrive in a wide variety of environmental conditions. It grows well in still and flowing waters, and can survive . . .

European naiad/ Spiny Naiad (Najas minor) Description:  Unlike most water plants, European naiad is a true annual. Seedlings grow from slender roots, developing stems up to 2.5 meters long that often branch abundantly near the top. Habitat:  European naiad is found in the underwater plant community, growing in ponds, lakes, and slow moving . . .

Description:  Hydrilla is a perennial underwater aquatic plant with long slender, branching stems rising from horizontal underground.  Identification of hydrilla is complicated by the fact that there are two distinct forms occurring in the United States.  Habitat:  Hydrilla is found in the underwater plant community. The adaptability of this plant to a wide . . .

Description: Chinese mystery snails are distinctively large; at the size of a walnut or golf ball, they are half-again as large as Maine’s largest native freshwater snail. Though they spend a good portion of their lives under the water surface, half buried in the bottom sediments, Chinese mystery snails may also . . .

Description:  Underwater stems rise from trailing, unbranched roots. Bright to dark green leaves are thickly arranged in groups of 4 to 6 leaves along slender stems. (Note: some lower leaves may occasionally occur in opposite pairs or in groups of 3 leaves.)  The small flowers (2 cm in diameter) have three . . .

Description:  Stems rise at intervals from slender roots. Fanwort has two distinct leaf types. Underwater leaves are finely divided, widely branched, and held apart from the stem on slender leaf stems, and looks like tiny fans with handles. The leaves are strictly arranged in opposite pairs along the main stem. The orderly formation of . . .

Description:  Long unbranched stems arise from roots and creeping underground stems. Unburied creeping underground stems function as a support structure for unusual roots, and provide resilience for developing growth. Developing stems may grow to a height of 30 cm above the water surface. Slender, feather-divided leaves occur along the trailing stems . . .

Description:  Rounded to heart-shaped floating leaves rise on long stalks from rooted stems. Each rooted stem supports a loosely branched group of several leaves. Note that all heart-shaped floating leaved plants that are native to Maine produce only one leaf per rooted stem. The leaves are typically wavy (shallowly scalloped) along . . .