Overview
Herbs, annual or perennial, caulescent or without evident stem, glabrous or pubescent, entirely submersed, with both submersed and floating leaves, or with submersed stolons and emergent leaves, in fresh, brackish, or marine waters; turions rarely present. Stems rhizomatous, creeping, with abbreviated erect axis at nodes, or erect, leafy, elongate. Leaves basal, alternate, opposite, or whorled, sessile or petiolate; stipules sometimes present, forming tubular sheath around stem; blade margins entire or serrate; veins 1--many. Infl orescences axillary, terminal, or scapose, 1-flowered or cymose, subtended by spathe; spathe a 2-fid bract or pair of opposite bracts. Flowers unisexual, staminate and pistillate on same plants or on different plants, often with rudiments of opposite type, or bisexual, actinomorphic, rarely slightly zygomorphic; perianth epigynous, free, mostly 6-parted, then differentiated into sepals and petals, rarely 3-parted, then petals absent in Thalassia and Halophila; stamens (0--) 2--many in 1 or more whorls (inner often staminodial), epigynous, distinct or ± connate; pollen spheric, in monads or tetrads or in slender chains; ovary 0--1, if present, inferior, 2--6[--16]-carpellate, 1-locular or falsely 6--9-locular; placentation parietal. Fruits berrylike. Seeds many, fusiform, ellipsoid, ovoid, or spheric; seed coat glabrous, papillose, or echinate.
Genera 17, species ca. 76 (10 genera, 14 species in the flora) : nearly worldwide.
Hydrocharitaceae, like other members of the Alismatidae, have one or more (fewer than 20) scales (intravaginal squamules) in the axils of their leaves. These scales (or hairs in some taxa) secrete mucilage and are without any venation. The structures are often referred to as "squamulae intravaginales" or "intravaginal scales" in the literature.[1]
Taxonomy
The Family Hydrocharitaceae is further organized into finer groupings including:
- Subfamily (4): Anacharidoideae · Hydrilloideae · Hydrocharitoideae · Stratioideae
- Tribe (1): Orchideae
- Genus (52): Aloides · Anacharis · Apalanthe · Appertiella · Barkania · Beneditaea · Blyxa · Boottia · Caulinia · Diplandra · Diplosiphon · Dominia · Egeria · Elodea · Enalus · Enhalus · Enhydrias · Fluvialis · Halophila · Herpophyllum · Hydora · Hydrilla · Hydrocharella · Hydrocharis · Hydrolirion · Hydromystria · Hydrospondylus · Hydrotrophus · Hymenotheca · Ittnera · Jalambicea · Lagarosiphon · Leptanthes · Limnobium · Luchia · Maidenia · Najas · Nechamandra · Oligolobos · Ottelia · Philotria · Physkium · Rhizakenia · Schizotheca · Serpicula · Stratiotes · Thalassia · Trianea · Tripteranthus · Udora · Vallisneria · Xystrolobos
- Species: ZipcodeZoo has pages for 723 species, subspecies, varieties, forms, and cultivars in the Family Hydrocharitaceae.
Genera
Aloides
Anacharis
Elodea is a genus of aquatic plants often called the waterweeds. Elodea is native to North America and is also widely used as aquarium vegetation. The introduction of some species of Elodea into waterways in parts of Europe, Australia, Africa, Asia, and New Zealand has created a significant problem and it is now considered a noxious weed in these areas. An older name for this genus is Anacharis, which serves as a common name in North America. [more]
Apalanthe
Appertiella
Barkania
Beneditaea
Blyxa
Plants annual [perennial], of fresh waters. Rhizomes absent [present]; stolons present. Erect stems rooted in substrate, unbranched short. Leaves basal, submersed, sessile; blade of uniform color from margin to margin, with continuous intercellular spaces, linear, base grading into sheath, apex acute; midvein without rows of lacunae along sides, uniform in color throughout from margin to margin, with continuous intercellular spaces; abaxial surfacely without prickles or aerenchyma; intravaginal squamules entire. Inflorescences 1-flowered, flowers rarely paired [cymose], long-pedunculate; spathe not winged. Flowers bisexual [unisexual, staminate and pistillate on different plants], emersed, pedicellate; petals white to reddish; filaments distinct; anthers fusiform; pollen in monads; ovary 1-locular; styles 1, not 2-fid. Fruits cylindric, ridged, dehiscing irregularly. Seeds ellipsoid or fusiform, echinate [without spines and with or without ridges or wings].[2] [more]
Boottia
Caulinia
Diplandra
Diplosiphon
Dominia
Dominia can refer to: [more]
Egeria
The name Egeria may refer to— [more]
Elodea
Elodea (syn. Anacharis) is a genus of aquatic plants often called the water weeds. Elodea is native to North America and it is also widely used as aquarium vegetation. The introduction of some species of Elodea into waterways in parts of Europe, Australia, Africa, Asia, and New Zealand has created a significant problem, and it is now considered a noxious weed in these areas [more]
Enalus
Enhalus
Enhydrias
Fluvialis
Halophila
Plants of marine waters. Rhizomes present; leaf-bearing branches arising from rhizome at each node; stolons absent. Erect stems, if present, rooted in substrate, unbranched, short; scales 2, midway or higher on stem. Leaves 2--8, terminal pairs or pseudowhorls [distichous], submersed, sessile or petiolate; blade linear to ovate, base tapering to stem; apex obtuse; midvein without lacunae along side(s), blade uniform in color throughout; abaxial surfacely without prickles; intravaginal squamules entire. Inflorescences 1-flowered or cymose, sessile; spathes not winged. Flowers unisexual, staminate and pistillate on same plants or on different plants, submersed, sessile, nearly sessile (pistillate), or pedicellate (staminate) ; petals absent. Staminate flowers: filaments distinct; anthers linear to fusiform; pollen in moniliform chains. Pistillate flowers: ovary 1-locular; styles 3--5, not 2-fid. Fruits ovoid to spheric, smooth or ridged, not echinate, dehiscing by decay of pericarp. Seeds spheric or nearly so, echinate to reticulate.[3] [more]
Herpophyllum
Hydora
A Genus in the Kingdom Plantae. [more]
Hydrilla
Hydrilla (Esthwaite Waterweed or Hydrilla) is an aquatic plant genus, usually treated as containing just one species, Hydrilla verticillata, though some botanists divide it into several species. Synonyms include H. asiatica, H. japonica, H. lithuanica, and H. ovalifolica. It is native to the cool and warm waters of the Old World in Asia, Europe, Africa and Australia, with a sparse, scattered distribution; in Europe, it is reported from Ireland, Great Britain, Germany, and the Baltic States, and in Australia from Northern Territory, Queensland, and New South Wales. . The stems grow up to 1?2 m long. The leaves are arranged in whorls of two to eight around the stem, each leaf 5?20 mm long and 0.7?2 mm broad, with serrations or small spines along the leaf margins; the leaf midrib is often reddish when fresh. It is monoecious (sometimes dioecious), with male and female flowers produced separately on a single plant; the flowers are small, with three sepals and three petals, the petals 3?5 mm long, transparent with red streaks. It reproduces primarily vegetatively by fragmentation and by rhizomes and turions (overwintering ), and flowers are rarely seen. [more]
Hydrocharella
Hydrocharis
Hydrocharis is a genus of aquatic plants within the family Hydrocharitaceae. [more]
Hydrolirion
Hydromystria
Hydrospondylus
Hydrotrophus
Hymenotheca
Ittnera
Jalambicea
Lagarosiphon
Leptanthes
Limnobium
Plants perennial, of fresh waters. Rhizomes absent; stolons floating on or suspended in water, rooted or not, unbranched, short. Leaves basal, emergent or floating, petiolate; blade elliptic to orbiculate, base reniform or cordate, apex obtuse to acuminate; midvein without rows of lacunae along sides, blade uniform in color throughout, abaxially surface without prickles, smooth on emergent leaves or with aerenchymous tissue on floating leaves; intravaginal squamules entire. Inflorescences cymose, sessile or short-pedunculate; spathe not winged. Flowers unisexual, staminate and pistillate on same plants, emersed, pedicellate; petals greenish white to yellowish. Staminate flowers: filaments connate at least ½ their length; anthers elongate; pollen in monads. Pistillate flowers: ovary 1-locular, falsely 6--9-locular; styles 3--9, 2-fid nearly to base. Fruits ellipsoid to spheric, smooth to ridged, dehiscing irregularly. Seeds ellipsoid, echinate, covered with blunt cylindric hairs.[4] [more]
Luchia
Maidenia
Najas
Najas is the botanical name of a genus of aquatic plants. It is cosmopolitan in distribution, totalling a few dozen species. It usually is taken as constituting (by itself) the family Najadaceae. [more]
Nechamandra
Oligolobos
Ottelia
Plants annual or perennial, of fresh waters. Rhizomes and stolons absent [present]. Erect stems rooted in substrate, unbranched, short. Leaves basal, submersed [floating], petiolate; blade lanceolate to reniform [linear], base cuneate to cordate, apex rounded to acute; midvein without rows of lacunae along sides, blade uniform in color throughout; abaxial surface without prickles or aerenchyma, smooth; intravaginal squamules entire. Inflorescences scapose, long-pedunculate; spathes winged or ribbed. Flowers bisexual [unisexual, staminate and pistillate on different plants], sessile [staminate pedicellate], floating or occasionally opening under water; petals white to pink or light violet, often yellow at base; filaments distinct; pollen in monads; ovary 1-locular; styles 3--9, not 2-fid. Fruits oblong, ridged, dehiscing irregularly. Seeds fusiform, covered with hairs.[5] [more]
Philotria
Physkium
Rhizakenia
Schizotheca
Serpicula
Stratiotes
Thalassia
Plants perennial, of marine waters. Rhizomes present; leaf-bearing branches arising from rhizomes at distances of several internodes; stolons absent. Erect stems rooted in substrate, unbranched, short. Leaves 2--6, basal, submersed, sessile; blade linear, base tapering to stem; apex obtuse; midvein without lacunae along side(s), blade uniform in color throughout; abaxial surfacely without prickles; intravaginal scales entire. Inflorescences 1-flowered to cymose, pedunculate; spathes not winged. Flowers unisexual, staminate and pistillate on different plants, submersed, short-pedicellate to nearly sessile; petals absent. Staminate flowers: filaments distinct; anthers linear; pollen embedded in gelatinous matrix, in moniliform chains. Pistillate flowers: ovary 1-locular; styles 6--8, not 2-fid. Fruits spheric, echinate, dehiscing into 6--8 irregular valves. Seeds pyriform; seed coat ephemeral.[6] [more]
Trianea
Tripteranthus
Udora
A Genus in the Kingdom Plantae. [more]
Vallisneria
Vallisneria is a genus of aquatic plant, commonly called eelgrass, tape grass or vallis. The genus has 6-10 species that are widely distributed, but do not grow in colder regions. [more]
Xystrolobos
More info about the Genus Xystrolobos may be found here.
Bibliography
- Ancibor, E. 1979. Systematic anatomy of vegetative organs of the Hydrocharitaceae. Bot. J. Linn. Soc. 78: 237--266.
- Catling, P. M. and W. G. Dore. 1982. Status and identification of Hydrocharis morsus-ranae and Limnobium spongia (Hydrocharitaceae) in northeastern North America. Rhodora 84: 523--545.
- Cook, C. D. K. , and K. Urmi-König. 1983. A revision of the genus Limnobium including Hydromystria (Hydrocharitaceae). Aquatic Bot. 17: 1--27.
- Cook, C. D. K. 1982. Pollinating mechanisms in the Hydrocharitaceae. In: J.-J. Symoens et al., eds. 1982. Studies on Aquatic Vascular Plants. Brussels. Pp. 1--15.
- Cook, C. D. K. and K. Urmi-König. 1984. A revision of the genus Ottelia (Hydrocharitaceae). 2. The species of Eurasia, Australasia, and America. Aquatic Bot. 20: 131--177.
- Cook, C. D. K., J.-J. Symoens, and K. Urmi-König. 1984. A revision of the genus Ottelia (Hydrocharitaceae). I1. Generic considerations. Aquatic Bot. 18: 263--274.
- Cook, C. D. K., and R. Lüönd. 1983. A revision of the genus Blyxa (Hydrocharitaceae). Aquatic Bot. 15: 1--52.
- Díaz-Miranda, D., D. Philcox, and P. Denny. 1981. Taxonomic clarification of Limnobium Rich. and Hydromystria G. W. F. Meyer (Hydrocharitaceae). Bot. J. Linn. Soc. 83: 311--323.
- Doty, M. S. and B. C. Stone. 1967. Typification for the generic name Halophila Thouars. Taxon 16: 414--418.
- Eiseman, N. J. and C. McMillan. 1980. A new species of seagrass, Halophila johnsonii, from the Atlantic coast of Florida. Aquatic Bot. 9: 15--19.
- Godfrey, R. K. and J. W. Wooten. 1979. Aquatic and Wetland Plants of Southeastern United States:. Monocotyledons. Athens, Ga.
- Grey, W. F. and M. D. Moffler. 1978. Flowering of the seagrass Thalassia testudinum (Hydrocharitaceae) in the Tampa Bay, Florida area. Aquatic Bot. 5: 251--259.
- Hartog, C. den. 1959. A key to the species of Halophila (Hydrocharitaceae), with descriptions of the American species. Acta Bot. Neerl. 8: 484--489.
- Hartog, C. den. 1970. The Sea-grasses of the World. Amsterdam.
- Holmes, W. C. 1978. Range extension for Ottelia alismoides (L.) Pers. (Hydrocharitaceae). Castanea 43: 193--194.
- Hunziker, A. T. 1982. Observaciones biológicas y taxonómicas sobre Hydromystria laevigata (Hydrocharitaceae). Taxon 31: 472--477.
- Hunziker, A. T. 1981. Hydromystria laevigata (Hydrocharitaceae) en el centro de Argentina. Lorentzia 4: 5--8.
- Moffler, M. D., M. J. Durako, and W. F. Grey. 1981. Observations on the reproductive ecology of Thalassia testudinum (Hydrocharitaceae) in Tampa Bay, Florida. Aquatic Bot. 10: 183--187.
- Moore, D. R. 1963. Distribution of the sea grass, Thalassia, in the United States. Bull. Mar. Sci. Gulf Caribbean 13: 329--342.
- Orpurt, P. R. and L. L. Boral. 1964. The flowers and seeds of Thalassia testudinum König. Bull. Mar. Sci. Gulf Caribbean 14: 296--302.
- Sachet, M.-H. and F. R. Fosberg. 1973. Remarks on Halophila (Hydrocharitaceae). Taxon 22: 439--443.
- Short, F. T. and M. L. Cambridge. 1984. Male flowers of Halophila engelmanii: Description and flowering ecology. Aquatic Bot. 18: 413--416.
- Thieret, J. W., R. R. Haynes, and D. H. Dike. 1969. Blyxa aubertii (Hydrocharitaceae) in Louisiana: New to North America. Sida 3: 343--344.
- Turner, C. E. 1980. Ottelia alismoides (L.) Pers. (Hydrocharitaceae) U.S.A., California. Madroño 27: 177.
- Wilder, G. J. 1974. Symmetry and development of Limnobium spongia (Hydrocharitaceae). Amer. J. Bot. 61: 624--642.
Footnotes
- Robert R. Haynes "Hydrocharitaceae". in Flora of North America Vol. 22. Oxford University Press. Online at EFloras.org.
- "Blyxa". in Flora of North America Vol. 22. Oxford University Press. Online at EFloras.org.
- "Halophila". in Flora of North America Vol. 22. Oxford University Press. Online at EFloras.org.
- "Limnobium". in Flora of North America Vol. 22. Oxford University Press. Online at EFloras.org.
- "Ottelia". in Flora of North America Vol. 22. Oxford University Press. Online at EFloras.org.
- "Thalassia". in Flora of North America Vol. 22. Oxford University Press. Online at EFloras.org.
Sources
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