''Brasenia'', commonly known as ''watershield'', 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 ...

belonging to the family

Cabombaceae The Cabombaceae are a family of aquatic, herbaceous flowering plants. A common name for its species is water shield. The family is recognised as distinct in the Angiosperm Phylogeny Group IV system (2016). The family consists of two genera of ...

, consisting of one species, ''Brasenia schreberi''. It is widely distributed in North America, the

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, northern

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(

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, Guyana), eastern

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( China, Japan,

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), Australia, the

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, and parts of

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.Kew World Checklist of Selected Plant Families
/ref> Junsai-asaproductinastore-march16-2014

''Brasenia'' is a perennial aquatic plant with floating,

peltate The following is a list of terms which are used to describe leaf morphology in the description and taxonomy of plants. Leaves may be simple (a single leaf blade or lamina) or compound (with several leaflets). The edge of the leaf may be regular ...

leaves and

rhizomatous 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 ho ...

stems. It is identified by its bright green leaves, small purple flowers that bloom from June through September, and a thick

mucilage Mucilage is a thick, gluey substance produced by nearly all plants and some microorganisms. These microorganisms include protists which use it for their locomotion. The direction of their movement is always opposite to that of the secretion of m ...

that covers all of the underwater organs, including the underside of the leaves, stems, and developing buds. This mucilage may be an anti-herbivore defence trait, perhaps to deter snail grazing. It grows in shallow water of lakes, rivers and beaver ponds, particularly those with somewhat acidic water.

Characteristics

Ponds along Attikamek Trail at Sault Ste

''Brasenia'' exhibits

wind pollination Anemophily or wind pollination is a form of pollination whereby pollen is distributed by wind. Almost all gymnosperms are anemophilous, as are many plants in the order Poales, including grasses, sedges, and rushes. Other common anemophilous plan ...

. The flowers have a two-day blooming period. On the first day, the functionally female, or pistillate flower, extends above the surface of the water and exposes the receptive stigmas. The flower then recedes below the water surface and on the following day emerges as a functionally male, or staminate flower. It is elevated higher than on the previous day and the anther-bearing filaments are extended beyond the female carpels. The anthers dehisce, releasing the pollen, and the flower is then withdrawn below the water where the fruit develops.

Uses

''Brasenia'' is cultivated as a vegetable in China (where it is known as ,

Pinyin Hanyu Pinyin (), often shortened to just pinyin, is the official romanization system for Standard Chinese, Standard Mandarin Chinese in China, and to some extent, in Singapore and Malaysia. It is often used to teach Mandarin, normally writte ...

: ) and where it is used in

Hangzhou Hangzhou ( or , ; , , Standard Mandarin pronunciation: ), also romanized as Hangchow, is the capital and most populous city of Zhejiang, China. It is located in the northwestern part of the province, sitting at the head of Hangzhou Bay, whic ...

in the well-known local speciality "West Lake Water Shield Soup () and in Japan (where it is known as '' junsai''). The mucilage it produces has been found to have anti-algal and anti-bacterial properties that may be useful as a natural weed control

History

Species of ''Brasenia'' occurred during the interglacial of Europe, but like many other aquatic plant species and genera, it does not occur there now.

Name

''Brasenia schreberi'' (syn. ''B. nymphoides'', ''B. peltata'') has the common name

water-shield Water-shield may refer to following aquatic plants: * ''Brasenia schreberi'' (water-shield) * ''Cabomba caroliniana ''Cabomba caroliniana'' is an aquatic perennial herbaceous plant native to North and South America. It is a weed of national s ...

(also watershield or water shield). The genus may commemorate the surgeon and Moravian missionary

Christoph Brasen Christoph is a male given name and surname. It is a German variant of Christopher. Notable people with the given name Christoph * Christoph Bach (1613–1661), German musician * Christoph Büchel (born 1966), Swiss artist * Christoph Dientzenhof ...

(1738-1774), who was the first superintendent of the Moravian mission at Nain in

Labrador , nickname = "The Big Land" , etymology = , subdivision_type = Country , subdivision_name = Canada , subdivision_type1 = Province , subdivision_name1 ...

.Pringle, James S. Possible eponymy of the generic name ''Brasenia'' Schreb. in Sida. vol. 16. no. 3. pp. 597-600. 1995

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References

External links