''Hymenachne'',

synonym A synonym is a word, morpheme, or phrase that means precisely or nearly the same as another word, morpheme, or phrase in a given language. For example, in the English language, the words ''begin'', ''start'', ''commence'', and ''initiate'' are a ...

''Dallwatsonia'', is a

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

of widespread

wetland A wetland is a distinct semi-aquatic ecosystem whose groundcovers are flooded or saturated in water, either permanently, for years or decades, or only seasonally. Flooding results in oxygen-poor ( anoxic) processes taking place, especially ...

plants in the grass family

Poaceae Poaceae ( ), also called Gramineae ( ), is a large and nearly ubiquitous family of monocotyledonous flowering plants commonly known as grasses. It includes the cereal grasses, bamboos, the grasses of natural grassland and species cultivate ...

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

tropical The tropics are the regions of Earth surrounding the equator, where the sun may shine directly overhead. This contrasts with the temperate or polar regions of Earth, where the Sun can never be directly overhead. This is because of Earth's ax ...

and

subtropical The subtropical zones or subtropics are geographical zone, geographical and Köppen climate classification, climate zones immediately to the Northern Hemisphere, north and Southern Hemisphere, south of the tropics. Geographically part of the Ge ...

regions of Asia, the Americas, and the

Pacific Islands The Pacific islands are a group of islands in the Pacific Ocean. They 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 several ...

.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 is an introduced species that harms its new environment. Invasive species adversely affect habitats and bioregions, causing ecological, environmental, and/or economic damage. The term can also be used for native spec ...

Description

''Hymenachne'' species are

aquatic plant Aquatic plants, also referred to as hydrophytes, are vascular plants and Non-vascular plant, non-vascular plants that have adapted to live in aquatic ecosystem, aquatic environments (marine ecosystem, saltwater or freshwater ecosystem, freshwater ...

s frequently found in marshes and other wet habitats. Their stems may be 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 ...

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

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

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

inflorescence In botany, an inflorescence is a group or cluster of flowers arranged on a plant's Plant stem, stem that is composed of a main branch or a system of branches. An inflorescence is categorized on the basis of the arrangement of flowers on a mai ...

is usually a cylindrical, spike-shaped

panicle In botany, 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 p ...

, rarely with branches.

Taxonomy

The genus ''Hymenachne'' was first described by Palisot de Beauvois in 1812. ''Hymenachne'' is similar to the genus '' Sacciolepis'', first described in 1901. Both were formerly considered part of '' Panicum''.''Hymenachne''.
Flora of China. Many species placed in ''Hymenachne'' have previously been placed in ''Sacciolepis''. In 1992, described a new genus ''Dallwatsonia'' for a single new Australian species he called ''Dallwatsonia felliana''. The genus was named for the Australian botanists Michael Dallwitz and Leslie Watson. In 2014, ten further species were transferred from '' Panicum'' to ''Dallwatsonia'' by José Ramón Grande Allende, who noted that ''Dallwatsonia'' was closely related to ''Hymenachne'', but could be distinguished by hollow rather than filled culms. However, a

molecular phylogenetic Molecular phylogenetics () is the branch of phylogeny that analyzes genetic, hereditary molecular differences, predominantly in DNA sequences, to gain information on an organism's evolutionary relationships. From these analyses, it is possible to ...

study published in 2014 supported the synonymy of ''Dallwatsonia'' and ''Hymenachne'', a conclusion also supported in a 2019 study. ,

Plants of the World Online Plants of the World Online (POWO) is an online taxonomic database published by the Royal Botanic Gardens, Kew. History Following the Convention on Biological Diversity, the Royal Botanic Gardens in Kew launched Plants of the World Online i ...

accepted ''Dallwatsonia'' as a synonym of ''Hymenachne''.

Species

, the following species were accepted:GRIN Species Records of ''Hymenachne''.
Germplasm Resources Information Network (GRIN) *'' Hymenachne amplexicaulis'' (Rudge) Nees – West Indian marsh grass, olive hymenachne –

West Indies The West Indies is an island subregion of the Americas, surrounded by the Atlantic Ocean, North Atlantic Ocean and the Caribbean Sea, which comprises 13 independent island country, island countries and 19 dependent territory, dependencies in thr ...

;

Latin America Latin America is the cultural region of the Americas where Romance languages are predominantly spoken, primarily Spanish language, Spanish and Portuguese language, Portuguese. Latin America is defined according to cultural identity, not geogr ...

from

Mexico Mexico, officially the United Mexican States, is a country in North America. It is the northernmost country in Latin America, and borders the United States to the north, and Guatemala and Belize to the southeast; while having maritime boundar ...

Uruguay Uruguay, officially the Oriental Republic of 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 the Río de la Plata to the south and the A ...

; naturalized in

Australia Australia, officially the Commonwealth of Australia, is a country comprising mainland Australia, the mainland of the Australia (continent), Australian continent, the island of Tasmania and list of islands of Australia, numerous smaller isl ...

, parts of

Asia Asia ( , ) is the largest continent in the world by both land area and population. It covers an area of more than 44 million square kilometres, about 30% of Earth's total land area and 8% of Earth's total surface area. The continent, which ...

Florida Florida ( ; ) is a U.S. state, state in the Southeastern United States, Southeastern region of the United States. It borders the Gulf of Mexico to the west, Alabama to the northwest, Georgia (U.S. state), Georgia to the north, the Atlantic ...

*'' Hymenachne assamica'' (Hook.f.) Hitchc. -

China China, officially the People's Republic of China (PRC), is a country in East Asia. With population of China, a population exceeding 1.4 billion, it is the list of countries by population (United Nations), second-most populous country after ...

Assam Assam (, , ) is a state in Northeast India, northeastern India, south of the eastern Himalayas along the Brahmaputra Valley, Brahmaputra and Barak River valleys. Assam covers an area of . It is the second largest state in Northeast India, nor ...

Myanmar Myanmar, officially the Republic of the Union of Myanmar; and also referred to as Burma (the official English name until 1989), is a country in northwest Southeast Asia. It is the largest country by area in Mainland Southeast Asia and has ...

Thailand Thailand, officially the Kingdom of Thailand and historically known as Siam (the official name until 1939), is a country in Southeast Asia on the Mainland Southeast Asia, Indochinese Peninsula. With a population of almost 66 million, it spa ...

*'' Hymenachne aurita'' (J.Presl ex Nees) Balansa *'' Hymenachne bresolinii'' (L.B.Sm. & Wassh.) Zuloaga *'' Hymenachne condensata'' (Bertol.) Chase *'' Hymenachne donacifolia'' (Raddi) Chase -

Cuba Cuba, officially the Republic of Cuba, is an island country, comprising the island of Cuba (largest island), Isla de la Juventud, and List of islands of Cuba, 4,195 islands, islets and cays surrounding the main island. It is located where the ...

Puerto Rico ; abbreviated PR), officially the Commonwealth of Puerto Rico, is a Government of Puerto Rico, self-governing Caribbean Geography of Puerto Rico, archipelago and island organized as an Territories of the United States, unincorporated territo ...

Trinidad Trinidad is the larger, more populous island of the Republic of Trinidad and Tobago, the country. The island lies off the northeastern coast of Venezuela and sits on the continental shelf of South America. It is the southernmost island in ...

;

from

Honduras Honduras, officially the Republic of Honduras, is a country in Central America. It is bordered to the west by Guatemala, to the southwest by El Salvador, to the southeast by Nicaragua, to the south by the Pacific Ocean at the Gulf of Fonseca, ...

Paraguay Paraguay, officially the Republic of Paraguay, is a landlocked country in South America. It is bordered by Argentina to the Argentina–Paraguay border, south and southwest, Brazil to the Brazil–Paraguay border, east and northeast, and Boli ...

*'' Hymenachne felliana'' (B.K.Simon) Zuloaga *'' Hymenachne grandis'' (Hitchc. & Chase) Zuloaga *'' Hymenachne grumosa'' (Nees) Zuloaga -

Brazil Brazil, officially the Federative Republic of Brazil, is the largest country in South America. It is the world's List of countries and dependencies by area, fifth-largest country by area and the List of countries and dependencies by population ...

Argentina Argentina, officially the Argentine Republic, is a country in the southern half of South America. It covers an area of , making it the List of South American countries by area, second-largest country in South America after Brazil, the fourt ...

*'' Hymenachne harleyi'' (Salariato, Morrone & Zuloaga) Zuloaga *'' Hymenachne leptachne'' (Döll) Zuloaga *'' Hymenachne longa'' (Hitchc. & Chase) Zuloaga *'' Hymenachne panduranganii'' J.Remya & Geethakum. *'' Hymenachne patens'' L.Liu -

(

Anhui Anhui is an inland Provinces of China, province located in East China. Its provincial capital and largest city is Hefei. The province is located across the basins of the Yangtze and Huai rivers, bordering Jiangsu and Zhejiang to the east, Jiang ...

Fujian Fujian is a provinces of China, province in East China, southeastern 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 capital is Fuzhou and its largest prefe ...

Jiangxi ; Gan: ) , translit_lang1_type2 = , translit_lang1_info2 = , translit_lang1_type3 = , translit_lang1_info3 = , image_map = Jiangxi in China (+all claims hatched).svg , mapsize = 275px , map_caption = Location ...

) *'' Hymenachne pernambucensis'' (Spreng.) Zuloaga -

*'' Hymenachne stagnatilis'' (Hitchc. & Chase) Zuloaga *'' Hymenachne wombaliensis'' Vanderyst ex Robyns - Zaïre ; Formerly included

References

{{Authority control Paspaleae Poaceae genera