POTAMOGETON NODOSUS
Family and Genus:- See- POTAMOGETONACEAE/Sect. POTAMOGETON
Common Name:- Longleaf pondweed, Loddon pondweed
Homotypic Synonyms:- None
Meaning:- Potamogeton (Gr) Watercourse - neighbour.
Nodosus (L) Many jointed, conspicuously jointed, knotty.
General description:- Rhizomatous perennial often growing in rather deep water.
Stem:-
1) Up to 3 m long, slender, sparingly branched.
Leaves:-
1) Submerged, short-petiolate, up to 20 x 4 cm, narrowly elliptic-lanceolate.
a) lower, 1 disintegrating at anthesis.
2) Floating, long-petiolate;
a) blade, usually 7-15 cm, elliptical (c. 3 times as long as broad), rounded to
cuneate at the base, subobtuse at the apex.
3) Stipules, large and conspicuous, 2-6 cm.
Flowers:-
1) Spike, on a long peduncle, emerging from the water, 2-5 x 0.5-1 cm.
2) Tepals, l.7-3 x 1.3-2.2 mm.
3) Anthers, elliptical, 0.8-1.7 x 0.3-0.5 mm.
Fruit:-
1) Fruitlets, glossy brown, obovate, strongly asymmetrical,
a) ventral zone flat,
b) dorsal zone, convex, shortly beaked, 2.5-4.3 x2-3 mm.
2) Beak. 0.2~0.9 mm.
Key features:-
1) Submerged leaves, lacking at anthesis or reduced to linear phyllodes;
2) Floating leaves, petiole of with a flexible discoloured joint at the top
Habitat:- Lakes, ponds, canals and stow-flowing streams, 0-1000 m,
Distribution:- Throughout Greece but not recorded from the Ionian lsiands. -
Widespread in Europe and almost cosmopolitan; native distribution uncertain
Flowering time:- May-August.
Photos by:- Giorgos Palimetakis
SPECIES DESCRIPTION