Pondweed Family:-

Pondweeds are " perennial waterweeds, usually growing in large clumps of stems 3-6 or more feet long, with submerged and sometimes floating leaves, which decay as the plant ripens. In most of our species each leaf has at its base a stipule, which may be erect and leaf-like or else sheath-like and enfolding the stem either completely or with the margins overlapping. Pondweeds are extremely variable, the size and shape of the leaves varying according to the composition, depth and speed of the water, and the age of the plant. Moreover they hybridise readily, some hybrids being not infrequent and persisting in the absence of one or both parents.

Their small greenish 4-sepalled petalless flowers are in stalked spikes at the base of the leaves, often projecting above the water but sinking again in fruit; anthers 4; stigmas 4. The fruits have 4 nutlets.

Pondweeds grow in many kinds of fresh and brackish water, still and moving, such as lakes, ponds, rivers, canals, streams and ditches. They may grow almost or quite uncovered, with stems a few inches long or rooting at the leaf-junctions." from Collins Pocket Guide to Wild Flowers by David McClintock and R.S.R. Fitter assisted by Francis Rose - ISBN 0 00 219363 9 - Eleventh Impression 1978

Pondweed Family plant table with its Common Name - Botanical Name. Flowering Months Range. Habitat with link to that Wild Flower Habitat Gallery:-

Common Name

Botanical Name

Flowering Months

Habitat

American Pondweed

(Ribbonleaf Pondweed,

Potamogeton epihydrus

June-August

In the Outer Hebrides, this rhizomatous perennial grows in a few peaty lochans, in oligotrophic and base-poor water less than 1 m deep. It is also established in the mesotrophic Rochdale Canal and Calder & Hebble Navigation in N. England. Lowland.

Flower

Flowers

Foliage

Form

Blunt-leaved Pondweed

(Grassy Pondweed)

Potamogeton obtusifolius

June-September

A rhizomatous perennial characteristically found in mesotrophic or meso-eutrophic, acidic or neutral standing waters in lakes, ponds and flooded mineral workings, or in canals and the backwaters of rivers. It may, however, occupy a broader habitat range in areas such as N. Ireland where it is especially frequent. It fruits freely, and also reproduces by turions. 0-480 m (Angle Tarn, Patterdale, Westmorland).

Flower

Flowers

Foliage

Form

Bog Pondweed

Potamogeton polygonifolius

May onwards

This rhizomatous perennial herb may grow as an aquatic in shallow water in lakes, pools, the backwaters of rivers, streams and ditches, or in a dwarf, subterrestrial state in wet Sphagnum lawns or `brown moss` communities. It is usually restricted to acidic water, only rarely occurring in highly calcareous but nutrient-poor sites. 0-780 m (Lochan an Tairbh-uisge, Mid Perth).

Flower

Foliage

Form

Broad-leaved Pondweed

Potamogeton natans

May-September

This rhizomatous perennial herb is frequent as a floating-leaved aquatic in still or slowly flowing waters, and more rarely found as plants with submerged phyllodes in more rapid streams and rivers. It has a very wide ecological tolerance, growing in oligotrophic to eutrophic and base-poor to base-rich water over a wide range of substrates. Although it may be found in shallow swamps, or in water over 5 m deep, it is most frequent at moderate depths of 1-2 metres. 0-760 m (below Stob Ban, Westerness).

Flower

Flowers at Goonhilly in Cornwall on 24 May

Foliage from Norfolk. Photo from BritishFlora

Form from Norfolk. Photo from BritishFlora

Flower at Goonhilly on 25 May

Flower Buds

Foliage at Graveney on 7 July

Form at Graveney on 7 July

Flower at Goonhilly on 25 May

Flowers at Graveney on 7 July

Form at Graveney on 7 July

Curly Pondweed

Potamogeton crispus

May onwards

It is a rhizomatous perennial which grows in a wide range of mesotrophic or eutrophic waters. These include lakes, ponds, rivers, streams, canals, ditches and disused mineral workings. It is more tolerant of eutrophication than most British Potamogeton species. Generally lowland, but reaching 350 m at Drumore Loch (E. Perth).

Flower

Flowers

Foliage

Form

Fennel Pondweed

Potamogeton pectinatus

June-September

This rhizomatous, linear-leaved aquatic is a characteristic species of eutrophic or brackish waters, where it may form dense stands in lakes, reservoirs, rivers, streams, canals, ditches, ponds and flooded mineral workings. It is tolerant of disturbance in canals and navigable rivers. It is occasionally found in highly calcareous but nutrient-poor lakes. Lowland.

Flower

Flowers

Foliage

Form

Flat-stalked Pondweed

Potamogeton friesii

June-August

A rhizomatous perennial of calcareous and often rather eutrophic, still or very slowly flowing waters. These include lakes, sluggish rivers and streams, canals, fenland lodes and flooded mineral workings. Lowland.

Flower

Flowers

Foliage

Form

Hairlike Pondweed

Potamogeton trichoides

June-September

It is found in a range of still or slowly flowing, mesotrophic or eutrophic waters including lakes, ponds, rivers, canals, ditches and flooded mineral workings. It often colonises disturbed sites such as recently cleared canals and ditches. Lowland.

Flower

Flowers

Foliage

Form

Lesser Pondweed

Potamogeton pusillus

June-September

A rhizomatous perennial found in standing or slowly flowing water in sheltered lakes and reservoirs, ponds, rivers, canals, ditches and flooded mineral workings. It favours mesotrophic to eutrophic water and tolerates slightly brackish conditions. 0-320 m (Stony Middleton, Derbys.).

Flower

Flowers

Foliage

Form

Loddon Pondweed

Potamogeton nodosus

August-September

This rhizomatous perennial herb is confined to a few calcareous and moderately eutrophic rivers. It grows in shallow or fairly deep water, apparently preferring gravelly substrates and avoiding soft clays. It reproduces vegetatively but does not fruit in Britain. Lowland.

Flower

Flowers

Foliage

Form

Long-stalked Pondweed

Potamogeton praelongus

May-August

No Potamogeton species is more characteristic of deep water than P. praelongus. It is a rhizomatous perennial that usually grows at depths greater than 1 m in clear, mesotrophic water in lakes, rivers, canals and major drains. It has only rarely been recorded from shallow water. 0-800 m (Loch Coire Cheap, Mid Perth).

Flower

Flowers

Foliage

Form

Opposite Pondweed

Groenlandia densa

(Potamogeton densus)

May-September

A perennial herb of shallow, clear, base-rich water which may grow in lakes and rivers, but is more frequent in smaller waters such as streams, canals, ditches and ponds. It rarely colonises newly available habitats, although it is sometimes found as an introduction in ponds. Generally lowland, but reaching 380 m at Malham Tarn (Mid-W. Yorks.).

Flower at Graveney on 7 July

Flowers

Foliage at Graveney on 7 July

Form at Graveney on 7 July

Perfoliate Pondweed

Potamogeton perfoliatus

June-September

A frequent macrophyte in larger water bodies, P. perfoliatus occasionally grows in oligotrophic sites but is more often found in mesotrophic or eutrophic conditions. It is a rhizomatous perennial that grows in shallow water in sites which are not prone to occasional desiccation, but is most vigorous at depths of 1 m or more. 0-780 m (Loch an Tairbh-uisge, Mid Perth).

Flower

Flowers

Foliage

Form

Plantain-leaved Pondweed

Potamogeton coloratus

May-July

This rhizomatous perennial herb is found in shallow, calcium-rich but nutrient-poor waters in lakes, pools, clay-pits, shallow streams and ditches. It grows over a range of substrates, including peat, marl, sand and clay. Lowland.

Flower

Flowers

Foliage

Form

Reddish Pondweed

(Red Pondweed)

Potamogeton alpinus

June-September

A rhizomatous perennial of still or slow-flowing water in lakes, rivers, canals, ditches and flooded mineral workings. P. alpinus is often found in sites where silt accumulates, such as lake inflows or backwaters in rivers. It characteristically grows in mesotrophic, often neutral or mildly acidic water. 0-945 m (Meall nan Tarmachan, Mid Perth).

Sharp-leaved Pondweed

Potamogeton acutifolius

June-July

This rhizomatous perennial has a very narrow habitat range, being confined to shallow, species-rich drainage ditches in lowland grazing marshes, where it typically grows in calcareous, mesotrophic or meso-eutrophic water. Although it fruits relatively freely and also produces turions, it shows little or no propensity to colonise new habitats. Lowland.

Flower

Flowers

Foliage

Form

Shining Pondweed

Potamogeton lucens

June-September

A rhizomatous perennial herb with submerged but no floating leaves, P. lucens grows in relatively deep, calcareous water in lakes, larger rivers, canals, flooded chalk- and gravel-pits and major fenland drains. It is found in clear, nutrient-poor, unpolluted waters as well as more eutrophic and turbid sites.

Flower

Flowers

Foliage

Form

Slender-leaved Pondweed

Potamogeton filiformis

May-August

This rhizomatous herb usually grows in open vegetation in the shallow edges of lakes. It is typically found over gravel, sand, silt or mud in sites where the water is base-rich, eutrophic or slightly brackish. It also occasionally grows in rivers, streams and ditches. 0-390 m at Drumore Loch (E. Perth), formerly at 735 m at Coire Dhubh-chlair (Mid Perth).

Flower

Flowers

Foliage

Form

Slender Pondweed

(Small Pondweed)

Potamogeton berchtoldii

June-September

A variable species which occurs in a wide range of still or slowly flowing waters, which may be base-rich or base-poor, oligotrophic, mesotrophic or eutrophic, and exposed or sheltered. P. berchtoldii is sometimes found in brackish sites, but is usually replaced in such habitats by P. pusillus. 0-710 m (Lochan nan Cat, Mid Perth).

Flower

Flowers

Foliage

Form

Various-leaved Pondweed

Potamogeton gramineus

June-August

This variable perennial is found in relatively shallow water in a variety of water bodies, including lakes, reservoirs, rivers, streams, canals and ditches. It tolerates a wide range of water quality, although it is absent both from the most acidic and oligotrophic sites and from the most eutrophic. It survives occasional, short-term desiccation.

Flower

Flowers

Foliage

Form

Wrack-like Pondweed

(Grass-wrack Pondweed)

Potamogeton compressus

June-August

P. compressus, a rhizomatous perennial, has been recorded from a wide range of habitats: lakes, sluggish rivers, ditches, canals and flooded mineral workings. Its sites share a tendency to be still or slowly flowing, mesotrophic and slightly to moderately base-rich. Lowland.

Flower

Flowers

Foliage

Form