The Brasenia genus and Brasenia schreberi J. F. Gmelin

Remark The words or terms in red (actually dark orange) in the text are defined in a glossary.


jul_07_02m.gthmb can't be loaded. Brasenia is a monotypic genus sporadically distributed throughout the Americas, Asia, Australia, and Africa, with Brasenia schreberi its single species. Brasenia is one of eight genera that comprise the two families of Nymphaeales (the water lilies) the Cabombaceae family (with the genera Brasenia and Cabomba) and the Nymphaeaceae family. The Nymphaeales are among the most primitive angiosperm.

Brasenia schreberi is a floating-leaved perennial plant that is native to North America. Its long leaf stalks reach all the way to the bottom where they attach to a long creeping root that is anchored in the mud. Its leaves are oval and shield-shaped. Its leaf stalks are attached at the centers of the leaf blades. Its submersed parts and undersides of leaves are covered with a viscous jelly-like substance. Its flowers are small, dull purple, and emerge from the water on a stalk. Its chromosome number (2n) is 80.

The plant belongs to the Cabombaceae family.

Name

The genus name, given by Johann Christian Daniel von Schreber is for Christoph Brasen (1738-1774) who might have been the first to collect and describe the plant. Christoph Brasen was a Danish surgeon, a Moravian missionary, and a plant collector in Greenland and Labrador. He was the first superintendent of the Nain Moravian mission in Labrador. He drowned in a storm that struck the 1774 expedition along the northern coast of Labrador. During a previous stay in Greenland, he had engaged in meteorological, botanical, mineralogical, and ornithological observations, to which a manuscript, entitled Some Natural Observations of Brother Brasen about the Weather, the Plants and Herbs, the Minerals and some Accompanying Birds testifies.

The schreberi epithet is the latinization de the name of a German botanist Johann Christian Daniel von Schreber (1739-1810), professor of natural history and director of the botanical garden at Erlangen, Bavaria; he was a student of Linnaeus.

Common names

Some of the vernacular names of Brasenia schreberi are: Water-shield, Watershield, Water-target, Dollar Bonnet and Purple Wen-dock. The French vernacular name is Brasénie de Schreber. draw_01.jpg can't be loaded.

Synonyms

Brasenia schreberi has also been known as:

Identification

Brasenia schreberi is easy to distinguish from water lilies and other plants with floating leaves by small oval leaves without a slit or notch. Furthermore, the clear gelatinous material coating stems and undersides of leaves is unique.

Description

Brasenia schreberi are aquatic herbs with floating leaves; their young vegetative parts heavily coated with mucilage.

Roots

Stems

Leaves

Flowers

Fruits

Habitat

Brasenia schreberi occurs in shallow lakes, in oligotrophic or mesotrophic ponds and slow streams, and prefers water up to six feet deep.

Distribution

map_world.jpg can't be loaded. Brasenia schreberi is generously sprinkled throughout the majority of the U.S. and in Canada; it is widespread but rarely common. It is found from Nova Scotia and Québec to Minnesota, south to Florida and Texas. In the west, it is found from British Columbia and western Montana to Washington and south to California. It is also found in Mexico, the West Indies, Central and South America, East Asia, Africa, and Australia. It is known from the fossil record in Europe although it is not known to grow there currently. The map on the left show the worldwide distribution; the map on the right shows the distribution for North America. map_na.jpg can't be loaded.

Notes

Brasenia schreberi reproduces sexually by seeds and asexually by rhizomes. In shallow ponds and lakes, Brasenia schreberi may be the dominant species, and its leaves may cover the entire water surface. Once established in an area, growth of other plants may well be inhibited by shading effects of the densely packed floating leaves. Very dense populations of water shield can impede small boat navigation and restrict recreational use. The seeds and vegetative parts are eaten by waterfowl.

In Japan, Brasenia schreberi is used as an ingredient of miso-shiru (the traditional miso soup). It is also cooked as Sumisoae or Sanbaizu. In China, it may be fried as food. When cooked with crucian carp and bean curd, the soup is said to be fragrant and tasty.

The plants are reported to have antibacterial, antialgal activity and to be allelopathic to lettuce seedlings.

Gallery

The photos of the gallery were taken either with one of the following: Minolta DiMAGE 7, Canon PowerShot A530, Canon Xt Rebel, usually with the EF-S60mm f/2.8 Macro USM objective, Fujifilm A 610 and EPSON Perfection 1650 (scanner). The title in the window shows the date when the picture was taken, i.e. jan_30_06... would mean that the photo was taken on the 30th of January, the 06 is for the 6th picture taken that day. The month, day and picture number might be followed by a letter which I use to identify the system used to take the picture.

Click on the thumbnails to get larger view. The original photos are usually in TIFF format, the photos shown are generally in JPEG format, often of dimensions one half (surface one quarter) for loading time reduction.

Habitat

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Plants, petiole

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Leaves

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Flowers

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