Hydrocharitaceae | |
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Common frogbit, Hydrocharis morsus-ranae | |
Scientific classification ![]() | |
Kingdom: | Plantae |
Clade: | Tracheophytes |
Clade: | Angiosperms |
Clade: | Monocots |
Order: | Alismatales |
Family: | Hydrocharitaceae Juss. [1] |
Genera | |
Hydrocharitaceae is a flowering plant family including 16 known genera with a total of ca 135 known species (Christenhusz & Byng 2016 [2] ), that including a number of species of aquatic plant, for instance the tape-grasses, the well known Canadian waterweed, and frogbit.
The family includes both freshwater and marine aquatics. They are found throughout the world in a wide variety of habitats, but are primarily tropical.
The species are annual or perennial, with a creeping monopodial rhizome with the leaves arranged in two vertical rows, or an erect main shoot with roots at the base and spirally arranged or whorled leaves. The leaves are simple and usually found submerged, though they may be found floating or partially emerse. As with many aquatics they can be quite variable in shape – from linear to orbicular, with or without a petiole, and with or without a sheathing base.
The flowers are arranged in a forked, spathe-like bract or between two opposite bracts. They are usually irregular, though in some case they may be slightly irregular, and either bisexual or unisexual. The perianth segments are in 1 or 2 series of 2–3 free segments; the inner series when present are usually showy and petal-like. Stamens 1–numerous, in 1 or more series; the inner ones sometimes sterile. pollen grains are globular and free but in the marine genera ( Thalassia and Halophila ) – the pollen grains are carried in chains, like strings of beads. The ovary is inferior with 2–15 united carpels containing a single locule with numerous ovules on parietal placentas which either protrude nearly to the centre of the ovary or are incompletely developed. Fruits are globular to linear, dry or pulpy, dehiscent or more usually indehiscent and opening by decay of the pericarp. Seeds are normally numerous with straight embryos and no endosperm.
Pollination can be extremely specialised.
The most recent phylogenetic treatment of the family recognizes four subfamilies. [3]
Some species have become established ornamental plants, and subsequently serious weeds in the wild (especially Egeria , Elodea and Hydrilla ).
Kubitzki (ed. 1998 [7] ) | data.kew [8] | APWeb (mobot.org) [9] | Watson & Dallwitz (delta-intkey) [10] |
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Hydrocharitaceae | |||
1. Ottelia | Ottelia Pers. (including Benedictaea Toledo, Boottia Wall.) (excludes Oligolobos Gagnep.) | Ottelia Persoon (including Benedictaea Toledo, Boottia Wallich, Oligolobos Gagnepain, Xystrolobus Gagnepain) | Ottelia |
2. Stratiotes | Stratiotes L. | Stratiotes L. | Stratiotes |
3. Hydrocharis | Hydrocharis L. | Hydrocharis L. | Hydrocharis |
4. Limnobium | Limnobium Rich. (including Hydromystria G.Mey. | Limnobium Richard (including Hydromystria G. Meyer) | Limnobium |
5. Blyxa | Blyxa Noronha ex Thouars (excludes Enhydrias Ridl.) | Blyxa Richard (including Enhydrias Ridley) | Blyxa |
6. Apalanthe | Apalanthe Planch. | (in Elodea Michaux) | Apalanthe |
7. Egeria | Egeria Planch. | Egeria Planchon | Egeria |
8. Elodea | Elodea Michx. (including Anacharis Rich., Udora Nutt.) | Elodea Michaux (including Anacharis Richard, Apalanthe Planchon, Hydora Besser, Philotria Rafinesque, Serpulica Pursh, Udora Nuttall) | Elodea |
9. Hydrilla | Hydrilla Rich. | Hydrilla Richard | Hydrilla |
10. Appertiella | Appertiella C.D.K.Cook & Triest | Appertiella C. D. K. Cook & Triest | Appertiella |
11. Lagarosiphon | Lagarosiphon Harv. | Lagarosiphon Harvey | Lagarosiphon |
12. Nechamandra | Nechamandra Planch. | Nechamandra Planchon | Nechamandra |
13. Maidenia | Maidenia Rendle | Maidenia Rendle | Maidenia |
14. Vallisneria | Vallisneria L. | Vallisneria L. | Vallisneria |
15. Enhalus | Enhalus Rich. | Enhalus Richard | Enhalus |
16. Thalassia | Thalassia Banks ex C.Koenig | Thalassia C. Koenig | Thalassia |
17. Halophila | Halophila Thouars | Halophila Thouars | Halophila |
(in Najas , Najadaceae) | Najas L. | Najas L. | (in Najas , Najadaceae) |
(name not found) | Enhydrias Ridl. | (in Blyxa , Hydrocharitaceae) | (name not found) |
(name not found) | Oligolobos Gagnep. | (in Ottelia , Hydrocharitaceae) | (name not found) |
Najadaceae | |||
1. Najas | (in Najas , Hydrocharitaceae) | (in Najas , Hydrocharitaceae) | Najas |
Asparagales is an order of plants in modern classification systems such as the Angiosperm Phylogeny Group (APG) and the Angiosperm Phylogeny Web. The order takes its name from the type family Asparagaceae and is placed in the monocots amongst the lilioid monocots. The order has only recently been recognized in classification systems. It was first put forward by Huber in 1977 and later taken up in the Dahlgren system of 1985 and then the APG in 1998, 2003 and 2009. Before this, many of its families were assigned to the old order Liliales, a very large order containing almost all monocots with colorful tepals and lacking starch in their endosperm. DNA sequence analysis indicated that many of the taxa previously included in Liliales should actually be redistributed over three orders, Liliales, Asparagales, and Dioscoreales. The boundaries of the Asparagales and of its families have undergone a series of changes in recent years; future research may lead to further changes and ultimately greater stability. In the APG circumscription, Asparagales is the largest order of monocots with 14 families, 1,122 genera, and about 36,000 species.
The Alismatales (alismatids) are an order of flowering plants including about 4,500 species. Plants assigned to this order are mostly tropical or aquatic. Some grow in fresh water, some in marine habitats. Perhaps the most important food crop in the order is the corm of the taro plant, Colocasia esculenta.
The Clusiaceae or GuttiferaeJuss. (1789) are a family of plants including 13 genera and ca 750 species. Several former members of Clusiacae are now placed in Calophyllaceae and Hypericaceae. They are mostly trees and shrubs, with milky sap and fruits or capsules for seeds. The family is primarily tropical. More so than many plant families, it shows large variation in plant morphology. According to the APG III, this family belongs to the order Malpighiales.
Iridaceae is a family of plants in order Asparagales, taking its name from the irises. It has a nearly global distribution, with 69 accepted genera with a total of c. 2500 species. It includes a number of economically important cultivated plants, such as species of Freesia, Gladiolus, and Crocus, as well as the crop saffron.
The Potamogetonaceae, commonly referred to as the pondweed family, is an aquatic family of monocotyledonous flowering plants. The roughly 110 known species are divided over six genera. The largest genus in the family by far is Potamogeton, which contains about 100 species.
Zosteraceae is a family of marine perennial flowering plants found in temperate and subtropical coastal waters, with the highest diversity located around Korea and Japan. Most seagrasses complete their entire life cycle under water, having filamentous pollen especially adapted to dispersion in an aquatic environment and ribbon-like leaves that lack stomata. Seagrasses are herbaceous and have prominent creeping rhizomes. A distinctive characteristic of the family is the presence of characteristic retinacules, which are present in all species except members of Zostera subgenus Zostera.
The family Pandaceae consists of three genera that were formerly recognized in the Euphorbiaceae. Those are:
Asparagaceae, known as the asparagus family, is a family of flowering plants, placed in the order Asparagales of the monocots. The family name is based on the edible garden asparagus, Asparagus officinalis. This family includes both common garden plants as well as common houseplants. The garden plants include asparagus, yucca, bluebell, and hosta, and the houseplants include snake plant, corn cane, spider plant, and plumosus fern.
Chrysobalanaceae is a family of flowering plants, consisting of trees and shrubs in 27 genera and about 700 species of pantropical distribution with a centre of diversity in the Amazon. Some of the species contain silica in their bodies for rigidity and so the mesophyll often has sclerenchymatous idioblasts. The widespread species Chrysobalanus icaco produces a plum-like fruit and the plant is commonly known as the coco plum.
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Ruppia, also known as the widgeonweeds, ditch grasses or widgeon grass, is the only extant genus in the family Ruppiaceae, with eight known species. These are aquatic plants widespread over much of the world. The genus name honours Heinrich Bernhard Rupp, a German botanist (1688-1719). They are widespread outside of frigid zones and the tropics.
Cymodoceaceae is a family of flowering plants, sometimes known as the "manatee-grass family", which includes only marine species.
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Galantheae is a tribe of European, West Asian and North African flowering plants belonging to the subfamily Amaryllidoideae of the Amaryllis family (Amaryllidaceae). As of 2017, it contains three genera, although more were included previously. The position of the ovary is inferior.
Stenomesseae was a tribe, where it forms part of the Andean clade, one of two American clades. The tribe was originally described by Traub in his monograph on the Amaryllidaceae in 1963, as Stenomessae based on the type genus Stenomesson. In 1995 it was recognised that Eustephieae was a distinct group separate from the other Stenomesseae. Subsequently, the Müller-Doblies' (1996) divided tribe Eustephieae into two subtribes, Stenomessinae and Eustephiinae.
Clinantheae is a tribe, where it forms part of the Andean clade, one of two American clades. The tribe was described in 2000 by Alan Meerow et al. as a result of a molecular phylogenetic study of the American Amaryllidoideae. This demonstrated that the tribe Stenomesseae, including the type genus Stenomesson was polyphyletic. Part of the tribe segregated with the Eucharideae and were submerged into it, while the other part formed a unique subclade. Since the type species of Stenomesson was not part of the second subclade, it was necessary to form a new name for the remaining species together with the other genera that remained. This was Clinanthus, the oldest name for these species, and consequently the tribe Clinantheae.