''Vossia'' is a

monotypic In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unispe ...

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 ...

in the grass family, found in

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 ...

and

Africa Africa is the world's second-largest and second-most populous continent, after Asia in both cases. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 6% of Earth's total surface area ...

. The only known species is ''Vossia cuspidata'',Kew World Checklist of Selected Plant Families
/ref> an aquatic grass native to

(from

Senegal Senegal,; Wolof: ''Senegaal''; Pulaar: 𞤅𞤫𞤲𞤫𞤺𞤢𞥄𞤤𞤭 (Senegaali); Arabic: السنغال ''As-Sinighal'') officially the Republic of Senegal,; Wolof: ''Réewum Senegaal''; Pulaar : 𞤈𞤫𞤲𞤣𞤢𞥄𞤲𞤣𞤭 ...

Egypt Egypt ( ar, مصر , ), officially the Arab Republic of Egypt, is a transcontinental country spanning the northeast corner of Africa and southwest corner of Asia via a land bridge formed by the Sinai Peninsula. It is bordered by the Medit ...

Somalia Somalia, , Osmanya script: 𐒈𐒝𐒑𐒛𐒐𐒘𐒕𐒖; ar, الصومال, aṣ-Ṣūmāl officially the Federal Republic of SomaliaThe ''Federal Republic of Somalia'' is the country's name per Article 1 of thProvisional Constituti ...

, south to

Namibia Namibia (, ), officially the Republic of Namibia, is a country in Southern Africa. Its western border is the Atlantic Ocean. It shares land borders with Zambia and Angola to the north, Botswana to the east and South Africa to the south and ea ...

), and to

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 ...

Bangladesh Bangladesh (}, ), officially the People's Republic of Bangladesh, is a country in South Asia. It is the eighth-most populous country in the world, with a population exceeding 165 million people in an area of . Bangladesh is among the mos ...

, and northern

Indochina Mainland Southeast Asia, also known as the Indochinese Peninsula or Indochina, is the continental portion of Southeast Asia. It lies east of the Indian subcontinent and south of Mainland China and is bordered by the Indian Ocean to the west an ...

. The common name is hippo grass.US Department of Agriculture plants profile
/ref> It is a thick-stemmed, hairy,

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 ...

, emergent, freshwater aquatic grass that can grow in dense stands in waters up to 5.5 metres in depth. The stems form a spongy mat as the

dry season The dry season is a yearly period of low rainfall, especially in the tropics. The weather in the tropics is dominated by the tropical rain belt, which moves from the northern to the southern tropics and back over the course of the year. The te ...

progresses. In the

Kafue Flats The Kafue Flats (locally called Butwa) are a vast area of swamp, open lagoon and seasonally inundated flood-plain on the Kafue River in the Southern, Central and Lusaka provinces of Zambia. They are a shallow flood plain 240 km long and a ...

region of

Zambia Zambia (), officially the Republic of Zambia, is a landlocked country at the crossroads of Central, Southern and East Africa, although it is typically referred to as being in Southern Africa at its most central point. Its neighbours are t ...

, it is the dominant plant of

eutrophic Eutrophication is the process by which an entire body of water, or parts of it, becomes progressively enriched with minerals and nutrients, particularly nitrogen and phosphorus. It has also been defined as "nutrient-induced increase in phytoplan ...

, slow-moving waters. It forms fairly monocultural stands with few other species, but shares this

habitat In ecology, the term habitat summarises the array of resources, physical and biotic factors that are present in an area, such as to support the survival and reproduction of a particular species. A species habitat can be seen as the physical ...

with the tiny free-floating aquatic carnivorous plant ''Utricularia gibba'' subsp. ''exoleta'' in sheltered areas where the waters are calm. Hippo grass can also be found here together with other plants in areas where different habitats meet, transitioning briefly with the herb '' Polygonum senegalense'' and elsewhere the tall cane '' Sorghum verticilliflorum'' along the banks of the main river course, as well as on the floodplains with the similar but annual aquatic grass '' Echinochloa stagnina'' and elsewhere with the water-lily ''

Nymphaea lotus ''Nymphaea lotus'', the white Egyptian lotus, tiger lotus, white lotus or Egyptian white water-lily, is a flowering plant of the family Nymphaeaceae. Distribution It grows in various parts of East Africa and Southeast Asia. The ''Nymphaea lot ...

''. In this area it is heavily grazed upon by huge herds of Kafue Flats lechwe, an antelope, which are largely dependent upon it in the dry season. This keeps the mat of stems in check, which allows other

herbaceous plant Herbaceous plants are vascular plants that have no persistent wood, woody stems above ground. This broad category of plants includes many perennial plant, perennials, and nearly all Annual plant, annuals and Biennial plant, biennials. Definition ...

s to colonise areas of open water, while at the same time freeing up grass seeds caught in the mat. These overgrazed areas thus create the habitat for some of the profusion of birdlife. When the waters rise as the annual floods in the Kafue Flats commence, upon regular occasion large chucks of ''Vossia'' and ''Echinochloa'' stems detach, and these slowly dying clumps of grass become wind-blown floating mats in the swamps, which host their own unique ecosystem, dominated by the sedge '' Pycreus mundii'', and further supporting the sedges '' Cyperus nudicaulis'', ''C. imbricatus'' and '' Scirpus cubensis'', and the herbs ''

Alternanthera sessilis ''Alternanthera sessilis'' is a flowering plant known by several common names, including sissoo spinach, Brazilian spinach, sessile joyweed and dwarf copperleaf. It is cultivated as a vegetable worldwide. Distribution The plant occurs throughout ...

'', '' Ipomoea mauritiana'', ''I. rubens'', ''Ludwigia stolonifera'', ''L. leptocarpa'' and a ''

Commelina ''Commelina'' is a genus of approximately 170 species commonly called dayflowers due to the short lives of their flowers. They are less often known as widow's tears. It is by far the largest genus of its family, Commelinaceae. The Swedish taxonom ...

'' species. In Zambia ''V. cuspidata'' flowers from January through May, with a peak at the end of March. It does not flower in years of drought on patches of land which do not flood. ;Formerly included see '' Phacelurus'' * '' Vossia cambogiensis'' - '' Phacelurus cambogiensis'' * '' Vossia speciosa'' - '' Phacelurus speciosus''

References

Panicoideae {{Poaceae-stub