Watershield - Brasenia schreberi

Family: Cabombaceae (Water-shield family) [E-flora]
Other Names: Water target [E-flora]

Pollution Leaves, Root, Mucilage Fodder Phthisis, Dysentery

Hazards

Food

Other Uses

Medicinal Uses

Description

Synonyms

General "growing to 0.1 m (0ft 4in) by 2 m (6ft)."[PFAF] Aquatic herb.[IFBC][E-flora]
Lifecycle Perennial. [PFAF]
Flowers "Solitary on 5-20 cm stalks".[IFBC][E-flora] "sepals and petals 3[HNW] (sometimes 4)[PCBC2004], linear-oblong, 10-18 mm. long, purplish;" [HNW] Single on long stalks. [PCBC2004]
Fruits Oblong, leathery.[IFBC] [E-flora] 6-8 mm. long.[HNW] "narrowly egg-shaped, ripening underwater and decaying to release the 1-2 seeds." [PCBC2004]
Leaves "Leaves floating, long-stalked, elliptic or oval".[IFBC][E-flora] Upper surface covered with a thick gelatinous coating. [HNW] Alternate, 3-12cm long, centrally attached to stalks 5-40cm long. [PCBC2004]
Stem Submerged, long, slender and branching.[PCBC2004]
Root "...from a slender rhizome" [IFBC][E-flora] creeping. [PCBC2004]
Habitat "Ponds and slow-moving streams".[IFBC][E-flora] Still and slow moving water. [HNW] Mostly at low elevations." [PCBC2004]
Range "common in SW BC"[IFBC][E-flora]
Status Native.[E-flora]
Similar Species This is a monotypic genus.[HNW]

Ethnobotany

"It is recommended as a local application in cancer, favus, and hemorrhoids." [ChineseMM]

Tincture: "The drug is steamed and dried nine times, and then digested in spirits. It is considered to be strengthening to the virile powers, and is used in the treatment of general debility and wasting." [ChineseMM]

Nutritional

Watershield - Brasenia schreberi [218-PFAF]

Part: Leaves Per 100 g dry weight
Food Energy (Kcal) 135 Ash (g) 63.5 Potassium (mg) -
Water (g) 0 Thiamine (mg) 0.41 Magnesium (mg) -
Protein (g) 9.5 Riboflavin (mg) - Calcium (mg) 122
Fat (g) 2.7 Niacin (mg) 0.05 Phosphorus (mg) 311
Carbohydrate (g) 24.3 Vitamin C (mg) - Sodium (mg) -
Fiber (g) 1.4 Vitamin A (RE) 135 Iron (mg) 27
Zinc (mg) - Manganese (mg) - Copper (mg) -

Notes: The figure for ash is remarkably high and needs to be verified.[k?]

Watershield - Brasenia schreberi [Turner&Kuhnlein]

Part:
Greens Per 100 g fresh weight
Food Energy (Kcal) 10 Ash (g) 4.7 Potassium (mg) 16
Water (g) 93 Thiamine (mg) 0.03 Magnesium (mg) 2.2
Protein (g) 0.7 Riboflavin (mg) 0.03 Calcium (mg) 15
Fat (g) 0.2 Niacin (mg) 0.3 Phosphorus (mg) 21
Carbohydrate (g) 1.8 Vitamin C (mg) - Sodium (mg) 18
Crude Fiber (g) 0.1 Vitamin A (RE) - Iron (mg) 11
Zinc (mg) 4.5 Manganese (mg) 18.5 Copper (mg) 0.5

The emergent vascular plants; 10.4% Dry matter, 8.8% Ash, 12.5% Crude protein, 4.71% Crude fat, 23.7% Cellulose, 11.8% Tannin, 3.79 Kcal/g Energy. [Boyd]

Pharmacology

Antithermic, anthelmintic and vulnerary.[ChineseMM]

Phytochemistry

Interest in the mucilage "has led to its characterization as a polysaaccharide with an extremely complicated structure".[Elakovich&Wooten]

Volatile Oil: 55 separated and identified components were noted. This consisted of "phenol, alkane, aldehyde, acid and alcohol, including methy-leugenol (25%), heptacosane (8.8%), 5-methyl furfural (8.0%), eucazulen (6.01%), carbamult (5.98%), cedrol (5.31%), π terpieol (3.77%), 4-terpineol (3.61%), cis-farnesol (3.36%), n-decanoic acid (3.35%), palmitic acid (3.01%), cis-6-dodecen-4-oli-de (2.8%), ethyl acetate (2.21%), eucalyptol (1.94%)" [Zhang Chi]

Antibacterial and antialgal activity. Its antibacterial activity may contribute to its rapid dominance. "Growth inhibition of the six additional standard bacterial strains suggests the antibacterial activity is broad-based rather than focused. This is underscored by the fact that both gram-negative and gram-positive bacteria and both eukaryotic and prokaryotic algae were inhibited." B. schreberi likely produces a series of allelochemicals.[Elakovich&Wooten]

Cultivation

"A floating plant producing stems up to 2 metres long[266], it should be grown in still lime-free water up to 1.8 metres deep[200]. Prefers a rich soil[200]. A good plant for the water's edge but it is difficult to establish[1]. The submerged parts of the plant are conspicuously covered in a mucilaginous jelly[274]. Plants are not fully hardy in Britain[56]. According to another report this species requires a minimum winter temperature of 18oc and can only be grown in aquaria and ponds in heated greenhouses[200]." [PFAF]

Invasive: Observations of sequences of events over a three-year period within dense populations of fragrant white waterlilies (Nymphaea odorata Ait.) indicate that once a single water shield propagule is established within the area, the species rapidly becomes dominant, leading to the exclusion of other species. The small size of the B. schreberi leaves relative to the waterlilies suggests that shading is not the principle competitive factor involved in water shield's rapid dominance. Both species are perennials, exhibit partial leaf retention throughout the winter, and resume spring growth at about the same time. [Elakovich&Wooten]

Allelopathic: Integrated approaches to aquatic plant management are increasingly considering use of allelopathic plant species. A search of the literature shows that most aquatic plants thus far reported to have allelopathic potential are not deep water plants. Thus B. schreberi with its antibacterial activity, its antialgal activity, and its ability to inhibit lettuce seedling radical growth is a promising candidate for allelopathic plant management of aquatic weeds. The ability of B. schreberi to inhibit the three bacterial strains cultured from lake water where the plant was collected, but not growing, suggest that its antibacterial activity may contribute to its rapid dominance. Growth inhibition of the six additional standard bacterial strains suggests the antibacterial activity of B. schreberi is broad-based rather than focused. This is underscored by the fact that both gram negative and gram-positive bacteria and both eukaryotic and prokaryotic algae were inhibited. The fact that inhibitory activity is displayed by the different fractions A - E and by the Skelly F, ether, and acetone Soxhlet extracts suggests that B. schreberi produces a series of allelochemicals. Studies are curently underway to determine the chemical nature of the allelochemicals of B. schreberi. [Elakovich&Wooten] "The plant has phytotoxic properties that allow it to inhibit the growth of other plants nearby and therefore allow it to become dominant. This gives it a potential for the natural control of invasive water weeds[274]." [PFAF]

Propagation

"Seed - no details have been found for this species. Seeds of many water plants have a short viability if allowed to dry out so it is probably best to sow the seed as soon as it is ripe in a warm greenhouse or to store it in water until the spring and to sow then. When they are large enough to handle, prick the seedlings out into individual pots and grow them on in the greenhouse for at least their first winter. Just cover the pots with water and then increase the depth as the plants grow. Plant them out into their permanent positions in late spring or early summer, after the last expected frosts. Division in spring[200]." [PFAF]

Watershield

Cabombaceae Family

1 sp. (C. Brasen, Danish surgeon, plant collector, 1738-1774)
Unabridged etymology: (Christoph Brasen, 1738-1774, Danish surgeon and plant collector, leader of the 1771 missionary expedition that established the Moravian mission of Nain on the coast of Labrador (Charters & Hollombe, pers. comm.)) [Jepson2012]

Local Species;

  1. Brasenia schreberi - Water Shield [E-flora][TSFTK]

References