Hydrocharitaceae is a
flowering plant
Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (), commonly called angiosperms. The term "angiosperm" is derived from the Greek words ('container, vessel') and ('seed'), and refers to those plants th ...
family including 16 known genera with a total of ca 135 known species (Christenhusz & Byng 2016
), 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.
Description
The species are
annual
Annual may refer to:
*Annual publication, periodical publications appearing regularly once per year
** Yearbook
** Literary annual
*Annual plant
*Annual report
*Annual giving
*Annual, Morocco, a settlement in northeastern Morocco
*Annuals (band), ...
or
perennial
A perennial plant or simply perennial is a plant that lives more than two years. The term ('' per-'' + '' -ennial'', "through the years") is often used to differentiate a plant from shorter-lived annuals and biennials. The term is also wid ...
, with a creeping monopodial
rhizome with the
leaves
A leaf (plural, : leaves) is any of the principal appendages of a vascular plant plant stem, stem, usually borne laterally aboveground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", wh ...
arranged in two vertical rows, or an erect main shoot with
root
In vascular plants, the roots are the organs of a plant that are modified to provide anchorage for the plant and take in water and nutrients into the plant body, which allows plants to grow taller and faster. They are most often below the su ...
s 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 very variable in shape – from linear to orbicular, with or without a
petiole, and with or without a sheathing base.
The
flower
A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants (plants of the division Angiospermae). The biological function of a flower is to facilitate reproduction, usually by providing a mechani ...
s 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
The perianth (perigonium, perigon or perigone in monocots) is the non-reproductive part of the flower, and structure that forms an envelope surrounding the sexual organs, consisting of the calyx (sepals) and the corolla ( petals) or tepals when ...
segments are in 1 or 2 series of 2–3 free segments; the inner series when present are usually showy and petal-like.
Stamen
The stamen (plural ''stamina'' or ''stamens'') is the pollen-producing reproductive organ of a flower. Collectively the stamens form the androecium., p. 10
Morphology and terminology
A stamen typically consists of a stalk called the filame ...
s 1–numerous, in 1 or more series; the inner ones sometimes sterile.
Pollen
Pollen is a powdery substance produced by seed plants. It consists of pollen grains (highly reduced microgametophytes), which produce male gametes (sperm cells). Pollen grains have a hard coat made of sporopollenin that protects the gametophyt ...
is globular and free but in the marine genera (''
Thalassia'' and ''
Halophila
''Halophila'' is a genus of seagrasses in the family ''Hydrocharitaceae'', the tape-grasses. It was described as a genus in 1806. The number of its contained species, and its own placement in the order Alismatales, has evolved.
Description
Th ...
'') – 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.
Fruit
In botany, a fruit is the seed-bearing structure in flowering plants that is formed from the ovary after flowering.
Fruits are the means by which flowering plants (also known as angiosperms) disseminate their seeds. Edible fruits in particu ...
s are globular to linear, dry or pulpy,
dehiscent or more usually indehiscent and opening by decay of the
pericarp
Fruit anatomy is the plant anatomy of the internal structure of fruit. Fruits are the mature ovary or ovaries of one or more flowers. They are found in three main anatomical categories: aggregate fruits, multiple fruits, and simple fruits. Aggr ...
.
Seed
A seed is an embryonic plant enclosed in a protective outer covering, along with a food reserve. The formation of the seed is a part of the process of reproduction in seed plants, the spermatophytes, including the gymnosperm and angiospe ...
s are normally numerous with straight
embryo
An embryo is an initial stage of development of a multicellular organism. In organisms that reproduce sexually, embryonic development is the part of the life cycle that begins just after fertilization of the female egg cell by the male spe ...
s and no
endosperm
The endosperm is a tissue produced inside the seeds of most of the flowering plants following double fertilization. It is triploid (meaning three chromosome sets per nucleus) in most species, which may be auxin-driven. It surrounds the embryo and ...
.
Pollination can be extremely specialised.
The most recent phylogenetic treatment of the family recognizes four
subfamilies –
Hydrocharitoideae (''
Hydrocharis
''Hydrocharis'' is a genus of aquatic plants in the family Hydrocharitaceae described as a genus by Carl Linnaeus in 1753. It is widespread across much of Europe and Asia, plus a few scattered locations in Africa. It is also reportedly naturaliz ...
'', ''
Limnobium
''Limnobium'', common names spongeplant and American frogbit, is a group of aquatic plants in the Hydrocharitaceae described as a genus in 1814. It is widespread in freshwater environments in Latin America, the West Indies, and the United States ...
''),
Stratiotoideae (''
Stratiotes
''Stratiotes'' is a genus of submerged aquatic plant commonly known as water soldiers, described as a genus by Linnaeus in 1753. Several specific names have been coined within the genus, but at present only one is recognized: '' Stratiotes aloi ...
''),
Anacharioideae (''
Apalanthe
''Elodea'' is a genus of 6 species of aquatic plants often called the waterweeds described as a genus in 1803. Classified in the frog's-bit family (Hydrocharitaceae), ''Elodea'' is native to the Americas and is also widely used as aquarium vegeta ...
'', ''
Appertiella'', ''
Blyxa
''Blyxa'' is a genus of an aquatic plant of the family Hydrocharitaceae described as a genus in 1806.
It is native to tropical and subtropical regions of Africa, Asia, Madagascar, and Australia
Australia, officially the Commonwealth of ...
'', ''
Egeria'', ''
Elodea
''Elodea'' is a genus of 6 species of aquatic plants often called the waterweeds described as a genus in 1803. Classified in the frog’s-bit family ( Hydrocharitaceae), ''Elodea'' is native to the Americas and is also widely used as aquarium ve ...
'', ''
Lagarosiphon
''Lagarosiphon'' is a genus of aquatic plants described as a genus in 1841. It is native to Africa and Madagascar. It is dioecious, with male and female flowers produced on separate plants.
Description
These branched, aquatic herbs are covere ...
'' and ''
Ottelia'') and
Hydrilloideae (''
Enhalus
''Enhalus'' is a monotypic genus of marine flowering plants. The sole species is ''Enhalus acoroides''. ''Enhalus'' is a large seagrass native to coastal waters of the tropical Indian and Western Pacific Oceans. It is the only species of seagr ...
'', ''
Halophila
''Halophila'' is a genus of seagrasses in the family ''Hydrocharitaceae'', the tape-grasses. It was described as a genus in 1806. The number of its contained species, and its own placement in the order Alismatales, has evolved.
Description
Th ...
'', ''
Hydrilla
''Hydrilla'' (waterthyme) is a genus of aquatic plant, usually treated as containing just one species, ''Hydrilla verticillata'', though some botanists divide it into several species. It is native to the cool and warm waters of the Old World in A ...
'', ''
Maidenia'', ''
Najas
''Najas'', the water-nymphs or naiads, is a genus of aquatic plants. It is cosmopolitan in distribution, first described for modern science by Linnaeus in 1753. Until 1997, it was rarely placed in the Hydrocharitaceae,Angiosperm Phylogeny Grou ...
'', ''
Nechamandra'', ''
Thalassia'' and ''
Vallisneria
''Vallisneria'' (named in honor of Antonio Vallisneri) is a genus of freshwater aquatic plant, commonly called eelgrass, tape grass or vallis. The genus is widely distributed in tropical and subtropical regions of Asia, Africa, Europe, and Nor ...
'').
Uses
Some species have become established
ornamental plant
Ornamental plants or garden plants are plants that are primarily grown for their beauty but also for qualities such as scent or how they shape physical space. Many flowering plants and garden varieties tend to be specially bred cultivars that i ...
s, and subsequently serious weeds in the wild (especially ''
Egeria'', ''
Elodea
''Elodea'' is a genus of 6 species of aquatic plants often called the waterweeds described as a genus in 1803. Classified in the frog’s-bit family ( Hydrocharitaceae), ''Elodea'' is native to the Americas and is also widely used as aquarium ve ...
'' and ''
Hydrilla
''Hydrilla'' (waterthyme) is a genus of aquatic plant, usually treated as containing just one species, ''Hydrilla verticillata'', though some botanists divide it into several species. It is native to the cool and warm waters of the Old World in A ...
'').
Genera
*''
Apalanthe
''Elodea'' is a genus of 6 species of aquatic plants often called the waterweeds described as a genus in 1803. Classified in the frog's-bit family (Hydrocharitaceae), ''Elodea'' is native to the Americas and is also widely used as aquarium vegeta ...
''
*''
Appertiella''
*''
Blyxa
''Blyxa'' is a genus of an aquatic plant of the family Hydrocharitaceae described as a genus in 1806.
It is native to tropical and subtropical regions of Africa, Asia, Madagascar, and Australia
Australia, officially the Commonwealth of ...
''
*''
Egeria''
*''
Elodea
''Elodea'' is a genus of 6 species of aquatic plants often called the waterweeds described as a genus in 1803. Classified in the frog’s-bit family ( Hydrocharitaceae), ''Elodea'' is native to the Americas and is also widely used as aquarium ve ...
''
*''
Enhalus
''Enhalus'' is a monotypic genus of marine flowering plants. The sole species is ''Enhalus acoroides''. ''Enhalus'' is a large seagrass native to coastal waters of the tropical Indian and Western Pacific Oceans. It is the only species of seagr ...
''
*''
Halophila
''Halophila'' is a genus of seagrasses in the family ''Hydrocharitaceae'', the tape-grasses. It was described as a genus in 1806. The number of its contained species, and its own placement in the order Alismatales, has evolved.
Description
Th ...
''
*''
Hydrilla
''Hydrilla'' (waterthyme) is a genus of aquatic plant, usually treated as containing just one species, ''Hydrilla verticillata'', though some botanists divide it into several species. It is native to the cool and warm waters of the Old World in A ...
''
*''
Hydrocharis
''Hydrocharis'' is a genus of aquatic plants in the family Hydrocharitaceae described as a genus by Carl Linnaeus in 1753. It is widespread across much of Europe and Asia, plus a few scattered locations in Africa. It is also reportedly naturaliz ...
''
*''
Lagarosiphon
''Lagarosiphon'' is a genus of aquatic plants described as a genus in 1841. It is native to Africa and Madagascar. It is dioecious, with male and female flowers produced on separate plants.
Description
These branched, aquatic herbs are covere ...
''
*''
Limnobium
''Limnobium'', common names spongeplant and American frogbit, is a group of aquatic plants in the Hydrocharitaceae described as a genus in 1814. It is widespread in freshwater environments in Latin America, the West Indies, and the United States ...
''
*''
Maidenia''
*''
Najas
''Najas'', the water-nymphs or naiads, is a genus of aquatic plants. It is cosmopolitan in distribution, first described for modern science by Linnaeus in 1753. Until 1997, it was rarely placed in the Hydrocharitaceae,Angiosperm Phylogeny Grou ...
''
Genera of Hydrocharitaceae
''GRIN Taxonomy for Plants''
*'' Nechamandra''
*'' Ottelia''
*''Stratiotes
''Stratiotes'' is a genus of submerged aquatic plant commonly known as water soldiers, described as a genus by Linnaeus in 1753. Several specific names have been coined within the genus, but at present only one is recognized: '' Stratiotes aloi ...
''
*'' Thalassia''
*''Vallisneria
''Vallisneria'' (named in honor of Antonio Vallisneri) is a genus of freshwater aquatic plant, commonly called eelgrass, tape grass or vallis. The genus is widely distributed in tropical and subtropical regions of Asia, Africa, Europe, and Nor ...
''
References
External links
*
*
*
{{Taxonbar, from=Q156029
Aquatic plants
Alismatales families