Potamogetonaceae
Potamogeton

Potamogeton trichoides Cham. & Schltdl.

First published in Linnaea 2: 175 (1827)
This species is accepted
The native range of this species is Europe to Central Asia, Canary Islands to N. Africa, Uganda to S. Africa. It is a hydroannual or hydrosubshrub and grows primarily in the temperate biome.

Descriptions

Potamogetonaceae, J.J. Symoens. Flora of Tropical East Africa. 2006

Morphology General Habit
Submerged aquatic herb.
Vegetative Multiplication Rhizomes
Rhizomes absent or only present at the end of the growing season, filiform, terete, sometimes developing terminal or axillary tubers.
Morphology General Buds
Turions apical or axillary, not greatly differing from the ordinary buds, but formed of more crowded leaves, darker and more rigid, detaching from the stem of the parent plant and easily dispersed by water (in the tropics ?).
Morphology Leaves
Submerged leavesbright green to dark green, often with a brownish tinge, sessile, linear, 14– 80(– 130) mm long, 0.3– 1(– 1.8) mm wide, 30– 110times as long as wide, narrowly cuneate at base, acuminate at apex, entire, 3-veined; midrib prominent, occupying 30– 70 per cent of the leaf width at the base, not bordered by rows of lacunae or lacunae poorly developed and confined to the basal half of the leaf; lateral veins sometimes inconspicuous, without additional sclerenchymatous strands; secondary and marginal veins absent; floating leaves absent; stipules axillary, open and tightly inrolled, 5– 27 mm long, translucent, often with a greenish tinge, obtuse at apex, persistent.
Morphology Reproductive morphology Inflorescences
Peduncles 10– 75 mm long, (2– )3– 9 times as long as the fruiting spike, as thick as the stem; spikes shortly cylindrical, 3– 9 mm long when in fruit, with 3– 5 flowers, contiguous to shortly distant near the base.
Morphology Reproductive morphology Flowers
Flowers 1(– 2)-carpellate.
Morphology Reproductive morphology Fruits
Fruitlets 2.5– 3.2 mm long; dorsal keel mostly distinct, often muriculate; beak 0.3– 0.5 mm long, straight.
Morphology Stem
Stem anatomy:stele of the circular type; endodermis of the O-type; interlacunar bundles absent; subepidermal bundles present; pseudohypodermis absent. Stems annual to perennial, up to 1.5 m long, sparingly to much branched, filiform, terete to slightly compressed, fragile and breaking easily at the nodes.
Habitat
Dams, ponds and seasonal pools; water depth 30– 50 cm; sometimes associated with Potamogeton pusillus; 1200– 2450 m
Distribution
K4 T7 U2 U4
[FTEA]

J. R. Timberlake, E. S. Martins (2009). Flora Zambesiaca, Vol 12 (part 2). Royal Botanic Gardens, Kew

Type
Type from Europe (many syntypes; lectotypification needed).
Morphology General Habit
Submerged aquatic herb
Vegetative Multiplication Rhizomes
Rhizomes absent or only present later in growing season, filiform, terete
Morphology Stem
Stems annual to perennial, up to 1.5 m long, sparingly to much branched, filiform, terete to slightly compressed, fragile and breaking easily at nodes; turions apical or axillary, not differing greatly from ordinary buds but formed of more crowded darker leaf, more rigid, detaching from stem of parent plant and readily dispersed by water Stem anatomy stele of circular type, endodermis of O-type; interlacunar bundles absent, subepidermal bundles present; pseudohypodermis absent.
Morphology Leaves Stipules
Stipules axillary, convolute, 5–27 mm long, translucent, often with a greenish tinge, persistent
Morphology Leaves
Floating leaf absent Submerged leaf sessile, linear, 14–80(130) 0.3–1(1.8) mm, (30)40–80(110) times as long as wide, bright green to dark green, often with a brownish tinge, narrowly cuneate at base, acuminate at apex, entire, 3-veined, midrib not bordered by rows of lacunae; lateral veins sometimes inconspicuous, without additional sclerenchyma strands, not bordered by a marginal vein
Morphology Reproductive morphology Inflorescences Peduncles
Peduncles 10–75 mm long, (2)3–9 times as long as fruiting spike, as thick as stem; spikes shortly cylindrical, 3–9 mm long in fruit, with flowers contiguous to ± closely spaced
Morphology Reproductive morphology Flowers
Flowers 3–5, carpels 1(2)
Morphology Reproductive morphology Fruits
Fruitlets 2.5–3.2 mm long; dorsal keel mostly distinct, often muriculate; beak 0.3–0.5 mm long, straight
Distribution
Botswana, Zimbabwe. Also in North Africa, tropical East Africa, Congo, South Africa (apparently rare). Also in Europe and W Asia.
Ecology
Dams, ponds, seasonal pools and watercourses at 30–50 cm depth; sometimes associated with P. pusillus; 1000–1500 m, to 2440 m in East Africa.
Conservation
Conservation notes Widely distributed; not threatened.
Recognition
As mentioned by Wiegleb & Kaplan (1998, p.298), this species is closely related to P. pusillus, from which it is sometimes difficult to distinguish in the vegetative stage from morphotypes with extremely narrow leaf. P. trichoides differs from P. pusillus by having open and convolute stipules and a leaf midrib occupying 30–70% of leaf width at the base. When in flower or in fruit, P. trichoides may be distinguished by its gynoecium reduced to 1 or 2 carpels and its fruitlets with a distinct dorsal keel.
[FZ]

IUCN Red List of Threatened Species https://www.iucnredlist.org/species/164357/84297799

Conservation
LC - least concern
[IUCN]

Extinction risk predictions for the world's flowering plants to support their conservation (2024). Bachman, S.P., Brown, M.J.M., Leão, T.C.C., Lughadha, E.N., Walker, B.E. https://nph.onlinelibrary.wiley.com/doi/full/10.1111/nph.19592

Conservation
Predicted extinction risk: not threatened. Confidence: confident
[AERP]

Sources

  • Angiosperm Extinction Risk Predictions v1

    • Angiosperm Threat Predictions
    • http://creativecommons.org/licenses/by/4.0

  • Flora Zambesiaca

    • Flora Zambesiaca
    • http://creativecommons.org/licenses/by-nc-sa/3.0

  • Flora of Tropical East Africa

    • Flora of Tropical East Africa
    • http://creativecommons.org/licenses/by-nc-sa/3.0

  • Herbarium Catalogue Specimens

    • Digital Image © Board of Trustees, RBG Kew http://creativecommons.org/licenses/by/3.0/

  • IUCN Categories

    • IUCN Red List of Threatened Species
    • http://creativecommons.org/licenses/by-nc-sa/3.0

  • Kew Backbone Distributions

    • The International Plant Names Index and World Checklist of Vascular Plants 2024. Published on the Internet at http://www.ipni.org and https://powo.science.kew.org/
    • © Copyright 2023 World Checklist of Vascular Plants. http://creativecommons.org/licenses/by/3.0

  • Kew Names and Taxonomic Backbone

    • The International Plant Names Index and World Checklist of Vascular Plants 2024. Published on the Internet at http://www.ipni.org and https://powo.science.kew.org/
    • © Copyright 2023 International Plant Names Index and World Checklist of Vascular Plants. http://creativecommons.org/licenses/by/3.0