Hydrocharitaceae

Vallisneria spiralis, copyright Lamiot.

Belongs within: Alismatanae.

The Hydrocharitaceae are a group of perennial herbs living at least partially submerged in water that are more diverse in warmer regions of the world.

Characters (from Healy & Edgar 1980): Aquatic perennials of fresh or salt water, partly or completely submersed; monoecious or dioecious. Stems long, slender, simple or branched, or 0. Leaves basal or cauline, usually sessile, alternate or whorled, variable in shape and size, submersed or floating. Flowers actinomorphic, commonly unisexual, sometimes bisexual. Inflorescence (or flower) sessile or long-pedunculate, in a tubular bifid spathe or within 2 opposite bracts; male flowers usually many within spathe; female flowers solitary; bisexual flowers solitary or several together. Perianth-segments usually 6 or fewer, in 1-2 whorls, 3 (rarely 2) in each whorl; tube often elongate. Stamens (1)-3-many, anthers 2-celled, opening by longitudinal slits (staminodia in female flowers). Ovary inferior, syncarpous, 1-locular, with 3-6 (rarely more) parietal placentae (rudimentary ovaries in male flowers); style-branches as many as placentae; stigmas entire or bifid; ovules many. Fruit submersed, often fleshy, indehiscent, occasionally rupturing irregularly. Seeds many.

<==Hydrocharitaceae [Hydrocharideae, Hydrocharitales]
    |--Elodea canadensis Michaux 1803 HE80
    |--Hydrocharis morsus-ranae BO08
    |--Lagarosiphon major (Ridley) Moss ex Wager 1928 HE80
    |--Stratiotes aloides YY22, C55
    |--Xystrolobos YY22
    |--Hydromystria YY22
    |--Enhalus acoroides P88
    |--Egeria densa Planchon 1849 HE80
    |--Boottia YY22
    |    |--B. aschersoniana M30
    |    `--B. muricata M30
    |--Hydrilla HE80
    |    |--H. kaynensis JD05
    |    `--H. verticillata HE80
    |--Thalassia Banks ex König 1805 HL09
    |    |--T. hemprichii (Ehrenberg) Aschersson 1871 [=Schizotheca hemprichii Ehrenberg 1832] HL09
    |    `--T. testudinum K-M02
    |--Halophila Thouars 1806 HL09
    |    |--H. decipiens Ostenfeld 1902 HL09
    |    |--H. ovalis (Brown) Hooker 1859 [=Caulinia ovalis Brown 1810] HL09
    |    `--H. stipulacea P71
    |--Blyxa YY22
    |    |--B. aubertii LK14
    |    |    |--B. a. var. aubertii LK14
    |    |    `--B. a. var. echinosperma LK14
    |    `--B. octandra LK14
    |--Ottelia HE80
    |    |--O. alismoides P88
    |    |--O. minutissima JD05
    |    |--O. ovalifolia (Brown) Richard 1811 HE80
    |    |    |--O. o. ssp. ovalifolia LK14
    |    |    `--O. o. ssp. chrysobasis LK14
    |    `--O. praeterita S87
    `--Vallisneria HE80
         |--V. americana B97
         |--V. annua LK14
         |--V. gigantea HE80
         |--V. nana LK14
         |--V. spiralis HE80
         |    |--V. s. var. spiralis PP07
         |    `--V. s. var. denseserrulata PP07
         |--V. stylosa JD05
         `--V. triptera LK14

*Type species of generic name indicated

REFERENCES

[BO08] Bönsel, D., I. Ottich, A. Malten & G. Zizka. 2008. An updated list of the vascular plants of Frankfurt am Main (Pteridophyta & Spermatophyta). Senckenbergiana Biologica 88 (1): 111–121.

[B97] Brown, K. M. 1997. Temporal and spatial patterns of abundance in the gastropod assemblage of a macrophyte bed. American Malacological Bulletin 14 (1): 27–33.

[C55] Candolle, A. de. 1855. Géographie Botanique Raisonée: Ou exposition des faits principaux et des lois concernant la distribution géographique des plantes de l’époque actuelle vol. 2. Librairie de Victor Masson: Paris.

[HE80] Healy, A. J., & E. Edgar. 1980. Flora of New Zealand vol. 3. Adventive cyperaceous, petalous and spathaceous monocotyledons. P. D. Hasselberg, Government Printer: Wellington (New Zealand).

[HL09] Huisman, J. M., F. Leliaert, H. Veerbruggen & R. A. Townsend. 2009. Marine benthic plants of Western Australia's shelf-edge atolls. Records of the Western Australian Museum Supplement 77: 50–87.

[JD05] Junge, F. W., M. Dolezych, H. Walther, T. Böttger, A. Kühl, L. Kunzmann, P. Morgenstern, T. Steinberg & R. Stange. 2005. Ein Fenster in Landschaft und Vegetation vor 37 Millionen Jahren: Lithologische, sedimentgeochemische und paläobotanische Befunde aus einem Paläoflusssystem des Weißelsterbeckens. Mauritiana 19 (2): 185–273.

[K-M02] Klein-MacPhee, G. 2002. Filefishes. Family Monacanthidae. In: Collette, B. B., & G. Klein-MacPhee (eds) Bigelow and Schroeder’s Fishes of the Gulf of Maine 3^rd ed. pp. 592–598. Smithsonian Institute Press: Washington.

[LK14] Lyons, M. N., G. J. Keighery, L. A. Gibson & T. Handasyde. 2014. Flora and vegetation communities of selected islands off the Kimberley coast of Western Australia. Records of the Western Australian Museum Supplement 81: 205–244.

[M30] Moss, C. E. 1930. A new genus of Hydrocharitaceae from tropical Africa. Proceedings of the Linnean Society of London 141: 14–16.

[PP07] Pandey, R. P., & P. M. Padhye. 2007. Studies on phytodiversity of Arid Machia Safari Park-Kailana in Jodhpur (Rajasthan). Bulletin of the Botanical Survey of India 49 (1–4): 15–78.

[P88] Polunin, I. 1988. Plants and Flowers of Malaysia. Times Editions: Singapore.

[P71] Por, F. D. 1971. One hundred years of Suez Canal—a century of Lessepsian migration: retrospect and viewpoints. Systematic Zoology 20 (2): 138–159.

[S87] Stephens, W. J. 1887. On the Biloela labyrinthodont (second notice). Proceedings of the Linnean Society of New South Wales, series 2, 1 (4): 1113–1121, pl. 14.

[YY22] Yampolsky, C., & H. Yampolsky. 1922. Distribution of sex forms in the phanerogamic flora. Bibliotheca Genetica 3: 1–62.