''Hymenachne'' is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...

of widespread

wetlands A wetland is a distinct ecosystem that is flooded or saturated by water, either permanently (for years or decades) or seasonally (for weeks or months). Flooding results in oxygen-free (anoxic) processes prevailing, especially in the soils. The p ...

plants that is in the

grass family Poaceae () or Gramineae () is a large and nearly ubiquitous family of monocotyledonous flowering plants commonly known as grasses. It includes the cereal grasses, bamboos and the grasses of natural grassland and species cultivated in lawns an ...

. They may be known commonly as marsh grasses. They are distributed in

tropical The tropics are the regions of Earth surrounding the Equator. They are defined in latitude by the Tropic of Cancer in the Northern Hemisphere at N and the Tropic of Capricorn in the Southern Hemisphere at S. The tropics are also referred to ...

and

subtropical The subtropical zones or subtropics are geographical and climate zones to the north and south of the tropics. Geographically part of the temperate zones of both hemispheres, they cover the middle latitudes from to approximately 35° north a ...

regions of Asia, the Americas, and the

Pacific Islands Collectively called the Pacific Islands, the islands in the Pacific Ocean are further categorized into three major island groups: Melanesia, Micronesia, and Polynesia. Depending on the context, the term ''Pacific Islands'' may refer to one of se ...

.Clarkson, J. R., et al. (2011)
A report of hybridisation in ''Hymenachne'' (Poaceae, Panicoideae) with description of ''Hymenachne'' × ''calamitosa'', a new species of hybrid origin from tropical Australia.
''Telopea'' 13(1-2), 105-14. A species from the Americas, ''H. amplexicaulis'', is well known in other parts of the world as an introduced and

invasive species An invasive species otherwise known as an alien is an introduced organism that becomes overpopulated and harms its new environment. Although most introduced species are neutral or beneficial with respect to other species, invasive species adv ...

. ''Hymenachne'' is similar to genus ''

Sacciolepis ''Sacciolepis'' is a genus of plants in the grass family. Cupscale grass is a common name for plants in this genus. They are widespread in tropical and warmer temperate regions. Many are native to Africa, with others in Asia, Australia, and th ...

''. Both were formerly considered part of ''

Panicum ''Panicum'' (panicgrass) is a large genus of about 450 species of grasses native throughout the tropical regions of the world, with a few species extending into the northern temperate zone. They are often large, annual or perennial grasses, growi ...

''.''Hymenachne''.
Flora of China. ''Hymenachne''

aquatic plant Aquatic plants are plants that have adapted to living in aquatic environments ( saltwater or freshwater). They are also referred to as hydrophytes or macrophytes to distinguish them from algae and other microphytes. A macrophyte is a plant that ...

s frequently found in marshes and other wet habitats. Their stems are spongy with

aerenchyma Aerenchyma or aeriferous parenchyma or lacunae, is a modification of the parenchyma to form a spongy tissue that creates spaces or air channels in the leaves, stems and roots of some plants, which allows exchange of gases between the shoot and th ...

tissue. The longest stems can reach 4 meters. They are perennial, sometimes with

rhizome In botany and dendrology, a rhizome (; , ) is a modified subterranean plant stem that sends out roots and shoots from its nodes. Rhizomes are also called creeping rootstalks or just rootstalks. Rhizomes develop from axillary buds and grow ...

s. The leaves are linear or lance-shaped.''Hymenachne''.
Grassbase - The World Online Grass Flora. The

inflorescence An inflorescence is a group or cluster of flowers arranged on a stem that is composed of a main branch or a complicated arrangement of branches. Morphologically, it is the modified part of the shoot of seed plants where flowers are forme ...

is usually a

cylindrical A cylinder (from ) has traditionally been a three-dimensional solid, one of the most basic of curvilinear geometric shapes. In elementary geometry, it is considered a prism with a circle as its base. A cylinder may also be defined as an in ...

, spike-shaped

panicle A panicle is a much-branched inflorescence. (softcover ). Some authors distinguish it from a compound spike inflorescence, by requiring that the flowers (and fruit) be pedicellate (having a single stem per flower). The branches of a panicle are of ...

, rarely with branches.

Diversity

; Accepted speciesKew World Checklist of Selected Plant Families
/ref>GRIN Species Records of ''Hymenachne''.
Germplasm Resources Information Network (GRIN) * ''

Hymenachne amplexicaulis ''Hymenachne amplexicaulis'', also known as West Indian marsh grass in the US, Olive hymenachne in Australia, and hereafter referred to as hymenachne, is New World species in the genus Genus ( plural genera ) is a taxonomic rank used in the ...

'' – West Indian marsh grass, olive hymenachne -

West Indies The West Indies is a subregion of North America, surrounded by the North Atlantic Ocean and the Caribbean Sea that includes 13 independent island countries and 18 dependencies and other territories in three major archipelagos: the Greate ...

;

Latin America Latin America or * french: Amérique Latine, link=no * ht, Amerik Latin, link=no * pt, América Latina, link=no, name=a, sometimes referred to as LatAm is a large cultural region in the Americas where Romance languages — languages derived ...

from

Mexico Mexico (Spanish language, Spanish: México), officially the United Mexican States, is a List of sovereign states, country in the southern portion of North America. It is borders of Mexico, bordered to the north by the United States; to the so ...

Uruguay Uruguay (; ), officially the Oriental Republic of Uruguay ( es, República Oriental del Uruguay), is a country in South America. It shares borders with Argentina to its west and southwest and Brazil to its north and northeast; while bordering ...

; naturalized in

Australia Australia, officially the Commonwealth of Australia, is a sovereign country comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands. With an area of , Australia is the largest country by ...

, parts of

Asia Asia (, ) is one of the world's most notable geographical regions, which is either considered a continent in its own right or a subcontinent of Eurasia, which shares the continental landmass of Afro-Eurasia with Africa. Asia covers an are ...

Florida Florida is a state located in the Southeastern region of the United States. Florida is bordered to the west by the Gulf of Mexico, to the northwest by Alabama, to the north by Georgia, to the east by the Bahamas and Atlantic Ocean, and ...

* '' Hymenachne assamica'' -

China China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's List of countries and dependencies by population, most populous country, with a Population of China, population exceeding 1.4 billion, slig ...

Assam Assam (; ) is a state in northeastern India, south of the eastern Himalayas along the Brahmaputra and Barak River valleys. Assam covers an area of . The state is bordered by Bhutan and Arunachal Pradesh to the north; Nagaland and Manipur ...

Myanmar Myanmar, ; UK pronunciations: US pronunciations incl. . Note: Wikipedia's IPA conventions require indicating /r/ even in British English although only some British English speakers pronounce r at the end of syllables. As John Wells explai ...

Thailand Thailand ( ), historically known as Siam () and officially the Kingdom of Thailand, is a country in Southeast Asia, located at the centre of the Indochinese Peninsula, spanning , with a population of almost 70 million. The country is b ...

* ''

Hymenachne donacifolia ''Hymenachne'' is a genus of widespread wetlands plants that is in the grass family. They may be known commonly as marsh grasses. They are distributed in tropical and subtropical regions of Asia, the Americas, and the Pacific Islands.Clarkson, J ...

'' -

Cuba Cuba ( , ), officially the Republic of Cuba ( es, República de Cuba, links=no ), is an island country comprising the island of Cuba, as well as Isla de la Juventud and several minor archipelagos. Cuba is located where the northern Caribb ...

Puerto Rico Puerto Rico (; abbreviated PR; tnq, Boriken, ''Borinquen''), officially the Commonwealth of Puerto Rico ( es, link=yes, Estado Libre Asociado de Puerto Rico, lit=Free Associated State of Puerto Rico), is a Caribbean island and unincorporated ...

Trinidad Trinidad is the larger and more populous of the two major islands of Trinidad and Tobago. The island lies off the northeastern coast of Venezuela and sits on the continental shelf of South America. It is often referred to as the southernmos ...

;

from

Honduras Honduras, officially the Republic of Honduras, is a country in Central America. The republic of Honduras is bordered to the west by Guatemala, to the southwest by El Salvador, to the southeast by Nicaragua, to the south by the Pacific Oce ...

Paraguay Paraguay (; ), officially the Republic of Paraguay ( es, República del Paraguay, links=no; gn, Tavakuairetã Paraguái, links=si), is a landlocked country in South America. It is bordered by Argentina to the south and southwest, Brazil to t ...

* '' Hymenachne grumosa'' -

Brazil Brazil ( pt, Brasil; ), officially the Federative Republic of Brazil (Portuguese: ), is the largest country in both South America and Latin America. At and with over 217 million people, Brazil is the world's fifth-largest country by area ...

Argentina Argentina (), officially the Argentine Republic ( es, link=no, República Argentina), is a country in the southern half of South America. Argentina covers an area of , making it the List of South American countries by area, second-largest ...

* '' Hymenachne patens'' -

(

Anhui Anhui , (; formerly romanized as Anhwei) is a landlocked province of the People's Republic of China, part of the East China region. Its provincial capital and largest city is Hefei. The province is located across the basins of the Yangtze Riv ...

Fujian Fujian (; alternately romanized as Fukien or Hokkien) is a province on the southeastern coast of China. Fujian is bordered by Zhejiang to the north, Jiangxi to the west, Guangdong to the south, and the Taiwan Strait to the east. Its ...

Jiangxi Jiangxi (; ; formerly romanized as Kiangsi or Chianghsi) is a landlocked province in the east of the People's Republic of China. Its major cities include Nanchang and Jiujiang. Spanning from the banks of the Yangtze river in the north int ...

) * '' Hymenachne pernambucense'' -

* '' Hymenachne wombaliensis'' -

Zaïre Zaire (, ), officially the Republic of Zaire (french: République du Zaïre, link=no, ), was a Congolese state from 1971 to 1997 in Central Africa that was previously and is now again known as the Democratic Republic of the Congo. Zaire was, ...

; formerly included see ''

Pennisetum ''Pennisetum'' is a widespread genus of plants in the grass family, native to tropical and warm temperate regions of the world. They are known commonly as fountaingrasses (fountain grasses).Sacciolepis ''Sacciolepis'' is a genus of plants in the grass family. Cupscale grass is a common name for plants in this genus. They are widespread in tropical and warmer temperate regions. Many are native to Africa, with others in Asia, Australia, and th ...

References

{{Taxonbar, from=Q2198236 Panicoideae Poaceae genera