Brasenia schreberi

J.F. Gmel.

Watershield

G5Secure Found in 38 roadless areas NatureServe Explorer →
G5SecureGlobal Rank
Least concernIUCN
LowThreat Impact
Identity
Unique IDELEMENT_GLOBAL.2.130243
Element CodePDCAB01010
Record TypeSPECIES
ClassificationSpecies
Classification StatusStandard
Name CategoryVascular Plant
IUCNLeast concern
Endemicoccurs (regularly, as a native taxon) in multiple nations
KingdomPlantae
PhylumAnthophyta
ClassDicotyledoneae
OrderNymphaeales
FamilyCabombaceae
GenusBrasenia
Other Common Names
Brasénie de Schreber (FR) Purple Wen-dock (EN) watershield (EN) Water-shield (EN)
Concept Reference
Kartesz, J.T. 1994. A synonymized checklist of the vascular flora of the United States, Canada, and Greenland. 2nd edition. 2 vols. Timber Press, Portland, OR.
Conservation Status
Rank Method Rank calculation - Biotics v2
Review Date2024-08-07
Change Date1984-02-16
Edition Date2024-08-07
Edition AuthorsNordman, C. (2024).
Threat ImpactLow
Range Extent>2,500,000 square km (greater than 1,000,000 square miles)
Number of Occurrences> 300
Rank Reasons
Watershield (Brasenia schreberi) is widespread globally, it occurs in North America, across the eastern and southeastern United States, southeastern Canada the Pacific Northwest, Mexico, Central America, West Indies, and in northern South America, equatorial Africa, eastern Asia, and eastern Australia. It is estimated that there are more than 3000 occurrences, rangewide. Threats include the loss of habitat due to dams and water management, and competition from aquatic invasive exotic plants. It occurs in the United States on various National Forests, National Wildlife Refuges, State Forests, and other conservation lands.
Range Extent Comments
Watershield (Brasenia schreberi) is widespread globally, it occurs in North America, across the eastern and southeastern United States, southeastern Canada the Pacific Northwest, Mexico, Central America, West Indies, and in northern South America, equatorial Africa, eastern Asia, and eastern Australia. Range extent was estimated to be 155 million square kilometers, using herbarium specimens and photo-based observations documented between 1993 and 2024 (FNA 1997, GBIF 2024, iNaturalist 2024, POWO 2024).
Occurrences Comments
By applying a 1 km separation distance to herbarium records and photo-based observations documented between 1993 and 2024, there are estimated to be more than 3000 occurrences rangewide (GBIF 2024, iNaturalist 2024).
Threat Impact Comments
Threats include the loss of habitat due to dams and water management, and competition from aquatic invasive exotic plants.
Ecology & Habitat

Description

Watershield (Brasenia schreberi) is a rhizomatous perennial aquatic herb with branches which rise through the water, floating leafblades (lily pads), and emergent flowers. The leaves have long petioles attached alternately to the branches and centrally to the undersides of the floating leaf blades. The broadly elliptic to oval leaf blades are 4-12 cm long and 3-8 cm wide. Solitary flowers are held just above the water on long peduncles. The flowers usually have 3 sepals and 3 petals which are similar, translucent reddish-purple colored, linear to lance-shaped, and 1-1.5 cm long. There are 4-14 pistils and 12-36 purplish stamens which are about the same length as the petals and sepals. The leathery, beaked fruits are 6-8 mm long and mature underwater.

Diagnostic Characteristics

Distinguished from other water lilies (NUPHAR, NYMPHAEA) by its relatively small, purplish, many pistilled flowers and by its relatively small, truly peltate (with petiole attached to the center of the blade) leaves.

Habitat

Watershield (Brasenia schreberi) occurs in "oligotrophic or mesotrophic ponds, lakes, and sluggish streams" at up to 2000 meters of elevation (FNA 1997).

Reproduction

Flowers in late spring and summer (FNA 1997).
Palustrine Habitats
HERBACEOUS WETLAND
Other Nations (2)
CanadaN5
ProvinceRankNative
Island of NewfoundlandS1Yes
New BrunswickS4Yes
British ColumbiaS5Yes
QuebecS4Yes
AlbertaS1Yes
Nova ScotiaS5Yes
Prince Edward IslandS1Yes
ManitobaS1Yes
OntarioS5Yes
United StatesN5
ProvinceRankNative
TexasSNRYes
MarylandS4Yes
West VirginiaS4Yes
IowaS2Yes
KentuckyS3Yes
WashingtonSNRYes
LouisianaSNRYes
ArkansasSNRYes
GeorgiaSNRYes
New HampshireSNRYes
NebraskaS2Yes
WisconsinSNRYes
MichiganSNRYes
PennsylvaniaSNRYes
OklahomaSNRYes
DelawareS4Yes
MontanaS1Yes
AlaskaS1Yes
New JerseyS4Yes
VermontS5Yes
New YorkS5Yes
OregonSNRYes
FloridaSNRYes
IllinoisS1Yes
Rhode IslandSNRYes
MinnesotaSNRYes
MissouriSNRYes
KansasSNRYes
South CarolinaS4Yes
CaliforniaS3Yes
MississippiSNRYes
MaineSNRYes
ConnecticutSNRYes
MassachusettsSNRYes
TennesseeSNRYes
District of ColumbiaSNRYes
IndianaS4Yes
OhioSNRYes
AlabamaSNRYes
IdahoSNRYes
North CarolinaS3Yes
VirginiaS5Yes
Threat Assessments
ThreatScopeSeverityTiming
7 - Natural system modificationsRestricted (11-30%)Moderate or 11-30% pop. declineHigh (continuing)
7.2 - Dams & water management/useRestricted (11-30%)Moderate or 11-30% pop. declineHigh (continuing)
8 - Invasive & other problematic species, genes & diseasesRestricted (11-30%)Moderate or 11-30% pop. declineHigh (continuing)
8.1 - Invasive non-native/alien species/diseasesRestricted (11-30%)Moderate or 11-30% pop. declineHigh (continuing)

Plant Characteristics
DurationPERENNIAL, SUMMER-FLOWERING
Economic Value (Genus)No
Roadless Areas (38)
California (8)
AreaForestAcres
Bucks LakePlumas National Forest680
Butt Mtn.Lassen National Forest8,217
DardanellesEldorado National Forest8,110
Middle ForkPlumas National Forest29,278
North MountainStanislaus National Forest7,856
PyramidEldorado National Forest24,347
SiskiyouKlamath National Forest54,039
Trail LakeLassen National Forest1,124
Florida (1)
AreaForestAcres
Farles PrairieOcala National Forest1,901
Michigan (1)
AreaForestAcres
Norwich Plains Revised Roadless AreaOttawa National Forest4,360
Minnesota (5)
AreaForestAcres
Baker - Homer - Brule LakesSuperior National Forest6,712
Baldpate LakeSuperior National Forest486
Hegman LakesSuperior National Forest675
Phantom LakeSuperior National Forest6,521
Wood LakeSuperior National Forest596
Montana (4)
AreaForestAcres
Bear - Marshall - Scapegoat - SwanLolo National Forest118,485
Buckhorn Ridge (MT)Kootenai National Forest34,716
Cabinet Face East #671Kootenai National Forest50,326
Scotchman Peaks (MT)Kootenai National Forest53,909
New Hampshire (2)
AreaForestAcres
Sandwich RangeWhite Mountain National Forest16,797
Wild RiverWhite Mountain National Forest46,878
Oregon (6)
AreaForestAcres
Brown Mt.Winema National Forest3,117
South KalmiopsisSiskiyou National Forests104,477
TahkenitchSiuslaw National Forest5,799
TenmileSiuslaw National Forest10,818
W. BoundaryWinema National Forest2,345
WoahinkSiuslaw National Forest5,309
Texas (1)
AreaForestAcres
Little Lake CreekNational Forests in Texas596
Vermont (1)
AreaForestAcres
Woodford 09086Green Mountain and Finger Lakes National Forests2,456
Virginia (3)
AreaForestAcres
James River AdditionJefferson National Forest1,140
Kelley MountainGeorge Washington National Forest7,590
Ramseys Draft AdditionGeorge Washington National Forest12,781
West Virginia (5)
AreaForestAcres
Canaan LoopMonongahela National Forest7,867
Cranberry AdditionMonongahela National Forest11,123
Falls Of Hills CreekMonongahela National Forest6,925
Glady ForkMonongahela National Forest3,239
Middle MountainMonongahela National Forest19,020
Wisconsin (1)
AreaForestAcres
09164 - Tea LakeChequamegon-Nicolet National Forest5,510
References (7)
  1. Flora of North America Editorial Committee (FNA). 1997. Flora of North America north of Mexico. Vol. 3. Magnoliophyta: Magnoliidae and Hamamelidae. Oxford Univ. Press, New York. xxiii + 590 pp.
  2. Frodge, J. D., G. L. Thomas, and G. B. Pauley. 1990. Effects of canopy formation by floating and submergent aquatic macrophytes on the water quality of two shallow Pacific Northwest lakes. Aquatic Botany 38(2):231-248.
  3. Global Biodiversity Information Facility (GBIF). 2024. Global Biodiversity Information Facility (GBIF) data portal. Online. Available: https://www.gbif.org/ (accessed 2024).
  4. iNaturalist. 2024. Online. Available: https://www.inaturalist.org (accessed 2024).
  5. Kartesz, J.T. 1994. A synonymized checklist of the vascular flora of the United States, Canada, and Greenland. 2nd edition. 2 vols. Timber Press, Portland, OR.
  6. Plants of the World Online (POWO). 2024. Plants of the World Online. Facilitated by the Royal Botanic Gardens, Kew. Online. Available: https://powo.science.kew.org/ (accessed 2024).
  7. Weakley, A.S., and Southeastern Flora Team. 2024. Flora of the southeastern United States. Edition of March 4, 2024. University of North Carolina Herbarium (NCU), North Carolina Botanical Garden, University of North Carolina, Chapel Hill. 2203 pp.