West Highland Flora

Slender-leaved Pondweed

Potamogeton filiformis


Potamogeton filiformis

Photo John Birks
Dept of Biology, Univ. of Bergen
Aug 2000 Greenland

Rare, in shallow water of lochs.

Leaves c 5-15 cm long, 0.5-1 mm wide.  Fruit c 2-3 mm long, 1.5-2 mm wide

ID: Stipules in two parts, first joined to the leaf and forming a sheath, then at the top of this sheath a projecting ligule.  The effect is rather like that of a grass leaf with its sheath and ligule.  To distinguish from Fennel-leaved Pondweed fruits are necessary.  These are rounded in the present species with the beak arising from near the centre of the top of the fruit.  In Fennel-leaved Pondweed the fruit is very asymmetrical and also larger.

Other features: Leaves tend to cling together more than in Fennel-leaved Pondweed which has them spread out in a fan-like way.

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