Ceratophyllum submersum L.

First published in Sp. Pl., ed. 2.: 1409 (1763)
This species is accepted
The native range of this species is Europe to Central Asia, Tropical Africa to S. Arabian Peninsula, Indian Subcontinent. It is a hydroannual or hydrosubshrub and grows primarily in the temperate biome.

Descriptions

Ceratophyllaceae, C.M. Wilmot-Dear. Flora of Tropical East Africa. 1985

Morphology General Habit
Very similar to C. demersum in form, but usually more delicate and filamentous in appearance, differing as follows.
Morphology Leaves
Leaves usually lighter green, 2–4 cm. long, branched dichotomously 3–4 times, sometimes one part of leaf branched more than another, rarely a few leaves of whorl only twice branched, usually rather fine, 0.1–0.3 mm. in diameter, but lower 1–2 segments sometimes swollen and up to 2.5 mm. across, marginal spiny teeth always minute, less than 0.1 or 0.2 mm., on lower 2 segments few or absent, few or more rarely numerous on final 2 segments.
sex Male
Male flowers up to 2 mm. in diameter; mature anthers 0.6–0.8 mm. long, 0.4–0.7 mm. wide (length 1–1.5 times width).
Morphology Reproductive morphology Flowers
Female perianth-segments usually longer, (1.5–)1.8–2 mm. long, 0.1–0.3 mm. wide, and relatively narrower (length (5–)7–10 times width). Male flowers up to 2 mm. in diameter; mature anthers 0.6–0.8 mm. long, 0.4–0.7 mm. wide (length 1–1.5 times width).
sex Female
Female perianth-segments usually longer, (1.5–)1.8–2 mm. long, 0.1–0.3 mm. wide, and relatively narrower (length (5–)7–10 times width).
Morphology Reproductive morphology Fruits
Mature fruit with apical spine less than 1 up to 9 mm.; surface sometimes with few large warts or spines.
[FTEA]

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]

IUCN Red List of Threatened Species https://www.iucnredlist.org/species/167833/96188202

Conservation
LC - least concern
[IUCN]

Ceratophyllaceae, C. M. Wilmot-Dear. Flora Zambesiaca 9:6. 1991

Morphology General Habit
Aquatic herb similar to Ceratophyllum demersum, but usually more delicate, differing as follows: Leaves usually lighter green, 2–4 cm. long, branching dichotomously 3–4 times (rarely twice in some whorls), usually rather fine, 0.1–0.3 mm. thick, to 2.5 mm. thick in lower segments, marginal teeth few, inconspicuous, often absent from lower segments, up to 0.1–0.2 mm. long.
sex Male
Male flowers to 2 mm. in diam.; anthers 0.6–0.8 x 0.4–0.7 mm., often smaller and relatively broader than in C. demersum.
Morphology Reproductive morphology Flowers
Female perianth lobes (1.5) 1.8–2 x 0.1–0.3 mm., relatively narrower and usually longer than in C. demersum. Male flowers to 2 mm. in diam.; anthers 0.6–0.8 x 0.4–0.7 mm., often smaller and relatively broader than in C. demersum.
sex Female
Female perianth lobes (1.5) 1.8–2 x 0.1–0.3 mm., relatively narrower and usually longer than in C. demersum.
Morphology Reproductive morphology Fruits
Fruit usually markedly laterally flattened with a marginal rim or wing.
[FZ]

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

  • 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
  • Kew Science Photographs

    • Copyright applied to individual images