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Naiads

Najas spp.

Naiads are bay grasses with short, narrow leaves along slender, branching stems. They grow in non-tidal fresh waters and fresh and brackish tidal portions of the Chesapeake Bay and its rivers.

Four species of naiads can be found in the Chesapeake Bay region:

• Spiny naiad (Najas minor)
• Southern naiad (Najas guadalupensis)
• Slender naiad (Najas gracillima)
• Northern naiad (Najas flexilis)

Appearance:

Naiads have slender, branching stems and short, narrow leaves with pointed tips and a broadened base. Their leaves grow opposite each other or in whorls along each stem. Their small, fibrous roots have no rhizomes or tubers. The spiny naiad has stiff, curved leaves with visible teeth along the edges. The southern naiad has flat, straight leaves that are wider than other naiads’ leaves.

Habitat:

Grows in non-tidal fresh waters and tidal fresh and brackish waters. Tolerates low light and prefers areas with a sandy bottom.

Range:

Ranges from small, non-tidal freshwater streams and ponds to fresh and slightly brackish tidal portions of the Chesapeake Bay and its rivers. The spiny naiad is native to Europe.

Predators:

Migratory waterfowl such as mallards, pintails and lesser scaup feed on southern naiad and northern naiad. Slender naiad is not nutritious enough for waterfowl.

Reproduction and Life Cycle:

Naiads reproduce sexually; each plant has both male and female flowers. After the flowers are pollinated, seeds form in late summer. Seeds germinate and grow into new plants the following spring.

Other Facts:

• Southern naiad is also known as bushy pondweed and water nymph.
• Although spiny naiad is not native to the Chesapeake Bay region, it is not considered invasive.
• Northern naiads are particularl sensitive to changes in water quality and increased pollution.

Sources and Additional Information:

• Underwater Grasses in Chesapeake Bay & Mid-Atlantic Coastal Waters by Maryland Sea Grant
• Life in the Chesapeake Bay by Alice Jane Lippson and Robert L. Lippson
• Bay Grass Key: Naiads – Maryland Department of Natural Resources
• Weed Identification Guide: Spiny Naiad – Virginia Tech

Places:

• Susquehanna River Water Trail – Lower Section – Harrisburg, Pennsylvania to Havre de Grace, Maryland
• Potomac River Water Trail – Washington, D.C. to Point Lookout, Maryland
• James River Water Trail – Richmond to Hampton Roads, Virginia