Potamogeton pusillus L.

First published in Sp. Pl.: 127 (1753)
This species is accepted
The native range of this species is Cosmopolitan. It is a hydroannual 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 later in the growing season,annual to biennial, filiform, terete, with short internodes.
Morphology Stem
Stems annual to perennial, up to 1 m long, 0.3– 0.7(– 1) mm in diameter, terete or compressed, sparingly to much branched. Stem anatomy:stele of the circular type; endodermis of the O-type; interlacunar bundles absent; subepidermal bundles present; pseudo-hypodermis mostly absent, if present 1-layered.
Morphology General Buds
Turions, when present, mostly sessile and axillary, but sometimes terminal on axillary branches, rigid, fusiform, with a few erect, patent or recurved free leaves.
Morphology Leaves
Submerged leaves bright green to olive green or dark green, sometimes with a brownish tinge, sessile, linear, (9– )20– 85(– 110) mm long, (0.3– ) 0.8– 2(– 2.5) mm wide, (15– )20– 90 times as long as wide, flaccid or firm, translucent, narrowly cuneate at base, tapering or rather abruptly narrowed to an acute or acuminate apex; margins entire, bordered by a narrow marginal vein; midrib occupying 15– 35 per cent of the leaf width at base, not bordered by lacunae or the lacunae poorly developed and restricted to the lower leaf half; lateral veins 1(– 2) on each side, distinct, joining the midrib 1.5– 4 leaf widths below the leaf apex; true floating leaves absent but rarely the uppermost leaves with lamina floating at the water surface, subsessile, linear-oblanceolate, 18– 38 mm long, 1.3– 3.1 mm wide, 7– 20 times as long as wide, bright green, narrowly cuneate at base, acute to narrowly obtuse at apex, 3– 5-veined, with broad rows of lacunae bordering the midrib; stipules axillary, connate and forming a tubular sheath at least in their lower part and when young, but splitting with age, 4– 18(– 32) mm long, translucent, persistent or decaying; turions mostly sessile and axillary, but sometimes also terminal on axillary branches, narrowlycylindrical, with a few erect, patent or recurved free leaves.
Morphology Reproductive morphology Inflorescences
Peduncles filiform to slightly clavate, ± flexuous, (6– )10– 30(– 55) mm long, 1– 6 times as long as the fruiting spike, as thick as the stem, slightly or distinctly compressed; spikes cylindrical, with 2– 7 flowers, in 1– 4 whorls, ± contiguous, sometimes the lowest flower remote, 4– 15 mm long in fruit.
Morphology Reproductive morphology Flowers
Tepals 0.8– 1.8 mm long, mostly persistent; carpels (3– )4(– 5); anthers 0.7– 0.9 mm long.
Morphology Reproductive morphology Fruits
Fruitlets obovoid, ± compressed, 1.8– 2.7 mm long, 1– 1.5 mm broad, green to pale olive, dorsally without keel, beak nearly centrally placed, straight or somewhat oblique, 0.2– 0.4 mm long.
Habitat
In lakes, dams and ponds, also in slow-flowing waters, sometimes in slightly brackish water; water depth 30– 60 cm; 600– 1700 m
Distribution
K3 K4 T7 U4 from Morocco to Libya and Egypt, also common in Europe and temperate parts of Asia, Arabia and North America, rarer in American and Asian tropics
[FTEA]

M. Thulin et al. Flora of Somalia, Vol. 1-4 [updated 2008] https://plants.jstor.org/collection/FLOS

Morphology General Habit
Submerged perennial with poorly developed slender rhizome, or arising from seeds or detached buds
Morphology Stem
Stems 20–100 cm long, strongly branched from the base; internodes of relatively equal length
Morphology Leaves
Leaves translucent, narrowly linear, 2–8 cm long and 1–2.5 mm wide, with 1 prominent midrib and 1(–2) weaker nerves on each side of the midrib, apiculate at the tip; sheath 5–18 mm long, tubular for more than half the length when young, later splitting almost to the base, light brown, semipersistent
Morphology Reproductive morphology Inflorescences
Spikes axillary, 4–12 mm long, 2–15-flowered, rarely interrupted; peduncles 1–3 cm long
Morphology Reproductive morphology Fruits
Fruit 2–2.5 x 1–1.5 mm, green to olive, obovoid and compressed with convex margins; keel obscure, rounded, smooth; beak 0.3–0.4 mm long, straight or somewhat oblique, almost centrally placed.
Distribution
N2 (“Medishe Springs”) scattered in Africa, more common in Europe and temperate parts of Asia and North America.
Ecology
Altitude c. 1800 m.
[FSOM]

Distribution
Biogeografic region: Andean. Elevation range: 2200–3919 m a.s.l. Native to Colombia. Colombian departments: Antioquia, Bogotá DC, Boyacá, Cundinamarca, Risaralda, Santander.
Habit
Herb, Aquatic.
Conservation
IUCN Red List Assessment (2021): LC.
[UPFC]

IUCN Red List of Threatened Species https://www.iucnredlist.org/species/163982/120218868

Conservation
LC - least concern
[IUCN]

Bernal, R., Gradstein, S.R. & Celis, M. (eds.). 2015. Catálogo de plantas y líquenes de Colombia. Instituto de Ciencias Naturales, Universidad Nacional de Colombia, Bogotá. http://catalogoplantasdecolombia.unal.edu.co

Distribution
Nativa en Colombia; Alt. 2200 - 3919 m.; Andes.
Morphology General Habit
Hierba, acuática
Conservation
No Evaluada
[CPLC]

Common Names

English
Small Pondweed

Sources

  • Catálogo de Plantas y Líquenes de Colombia

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

    • Flora of Somalia
    • 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 2023. Published on the Internet at http://www.ipni.org and https://powo.science.kew.org/
    • © Copyright 2022 World Checklist of Vascular Plants. http://creativecommons.org/licenses/by/3.0
  • Kew Living Collection Database

    • Common Names from Royal Botanic Gardens, Kew Living Collection https://www.kew.org/
  • Kew Names and Taxonomic Backbone

    • The International Plant Names Index and World Checklist of Vascular Plants 2023. Published on the Internet at http://www.ipni.org and https://powo.science.kew.org/
    • © Copyright 2022 International Plant Names Index and World Checklist of Vascular Plants. http://creativecommons.org/licenses/by/3.0
  • Useful Plants and Fungi of Colombia

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