Spiny naiad, holly-leaved naiad, sawtooth
- Scientific Name: Najas marina
- Origin: Almost cosmopolitan
- Type: Weed
- Plant Life-form Type: Submerged
- Taxonomy: L.
- Presence: Not known to be in NZ
- Habitat: Fresh and brackish water, and may be annual or perennial depending on the seasonality of the habitat
- Temperature (°C): 16 - 22
- pH range: 7.0 - 7.5
- Hardness (ppm): 100 - 200
- Notes: Potentially a major weed in New Zealand. Often found in stagnant water with a high percentage of organic mud.
- Propagation: Plant fragments and seed
- Features: N. marina is a rooted submerged aquatic plant and maybe annual or perennial depending on the habitat. It has stems up to 100 cm long, with a spiny appearance and few roots. The leaves are sessile, seemingly opposite or whorled, linear to lanceolate in shape (up to ca 4 to 6 cm long by 0.5 to 2.5 mm wide) and generally stiff. The leaf margins are coarsely toothed (triangular). Plants are dioecious, the male flowers have a spathe, the female flowers without.
- Source: TIFBIS