Flora of the Canadian Arctic Archipelago

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S.G. Aiken, M.J. Dallwitz, L.L. Consaul, C.L. McJannet, R.L. Boles, G.W. Argus, J.M. Gillett, P.J. Scott, R. Elven, M.C. LeBlanc, L.J. Gillespie, A.K. Brysting, H. Solstad, and J.G. Harris

Potamogetonaceae Dumortier

Potamogetonaceae, Pondweed family.

Vegetative morphology. Plants (5–)10–30 cm high (or more in deep, clear, "warm" water); perennial herbs; not caespitose; sometimes vegetatively proliferating by bulbils on stems or leaves. Only fibrous roots present. Ground level or underground stems horizontal; stoloniferous, or rhizomatous; elongate, or compact. Aerial stems plants aquatic without aerial stems; erect. Leaves distributed along the stems; alternate (all submerged); dying annually and non-persistent. Stipules present; sheathing; brown, or green; glabrous. Petioles absent. Leaves grass-like. Blades 25–100(–120) mm long, 0.2–0.7 mm wide (filiform). Leaves filiform. Blades linear, veins parallel. Blade margins glabrous; apices acute.

Reproductive morphology. Flowering stems without leaves. Inflorescences spicate. Flowers per inflorescence 6–14 (in 2–4 whorls); small. Sepals conventional; 4; free; green; fleshy. Calyx glabrous. Petals absent. Stamens 4. Ovary superior; carpels 4 (alternating with the stamens); apocarpous. Styles absent. Ovules per ovary 1. Fruit with calyx persisting; dry; an achene; spherical (slightly flattened); black, or brown (where seed shows through the thin green fruit wall); 1.8–2 mm long; 1.6–1.8 mm wide; indehiscent. Seeds 1; 0.3–0.4 mm long; brown; surfaces smooth (or with a slight ridge and a few tubercles).

General notes. There is an abundance of reported hybrids in the family, and nearly all of them can occur, at least locally, more or less independent of their parents. They also reproduce, albeit by vegetative means, may form very large 'stands' or clones, often in long stretches of rivers, and can be spread over long distances by birds.


This publication is available on the internet (posted May 2011) and on CD-ROM (published in 2007). These versions are identical in content, except that the errata page for CD-ROM is accessible on the main index page of the web version.

Recommended citation for the web-based version of this publication: Aiken, S.G., Dallwitz, M.J., Consaul, L.L., McJannet, C.L., Boles, R.L., Argus, G.W., Gillett, J.M., Scott, P.J., Elven, R., LeBlanc, M.C., Gillespie, L.J., Brysting, A.K., Solstad, H., and Harris, J.G. 2007. Flora of the Canadian Arctic Archipelago: Descriptions, Illustrations, Identification, and Information Retrieval. NRC Research Press, National Research Council of Canada, Ottawa. http://nature.ca/aaflora/data, accessed on DATE.

Recommended citation for the CD-ROM version of this publication: Aiken, S.G., Dallwitz, M.J., Consaul, L.L., McJannet, C.L., Boles, R.L., Argus, G.W., Gillett, J.M., Scott, P.J., Elven, R., LeBlanc, M.C., Gillespie, L.J., Brysting, A.K., Solstad, H., and Harris, J.G. 2007. Flora of the Canadian Arctic Archipelago: Descriptions, Illustrations, Identification, and Information Retrieval. [CD-ROM] NRC Research Press, National Research Council of Canada, Ottawa.

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