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

Hippuridaceae Link

English: Mare's tail family.

Hippuridaceae, Mare's tail family.

Vegetative morphology. Plants (4–)10–50(–150) cm high; perennial herbs; sometimes vegetatively proliferating by fragmentation. Only fibrous roots present. Roots developed from free-floating fragments. Ground level or underground stems horizontal (and semi-horizontal stems, rooting in soft substrates); rhizomatous (but rhizomes are rarely found on herbarium specimens); elongate, or compact. Aerial stems developed; erect. Leaves heterophyllous (particularly when plants grow in shallow water), or not heterophyllous (submerged plants); distributed along the stems; whorled; dying annually and non-persistent. Petioles absent. Leaf blades simple (undivided). Leaf blade bases truncate. Blades (2–)10–80 mm long (aerial leaves usually less than 15 mm long), 0.3–4 mm wide, divaricate, linear or lanceolate or oblanceolate, flat, appearing single-veined or with inconspicuous veins. Blade adaxial surface glabrous. Blade abaxial surface glabrous. Blade margins glabrous; apices acuminate.

Reproductive morphology. Flowering stems circular or oval in cross section. Flowering stems with leaves; rooting at the lower nodes (especially in soft mud). Flowers solitary (in the axil of a leaf). Pedicels absent. Involucral bracts absent. Flowers small; bilaterally symmetrical (zygomorphic) (very reduced); bisexual. Sepals absent (reduced to an inconspicuous 2–4 lobed or sub-entire rim around the top of the ovary). Petals absent. Stamens 1. Anthers purple (turning brown). Ovary inferior; carpels 1; monomerous (pseudo-monomerous). Ovaries glabrous. Styles present (elongate slender). Stigmas per ovary 1 (along the whole length of the style). Placentation apical. Ovules per ovary 1. Fruit sessile; dry; an achene; spherical, or oblong; brown (dark brown or blackish); (1.6–)1.8–2 mm long; 0.7–1.2 mm wide; glabrous; surface appearing veinless; not distinctly flattened; indehiscent. Seeds 1.


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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