Roadless Areas
Home/Species/ Common Water-willow

Justicia americana

(L.) Vahl

Common Water-willow

G5Secure Found in 19 roadless areas NatureServe Explorer →
G5SecureGlobal Rank
Least concernIUCN
LowThreat Impact
Identity
Unique IDELEMENT_GLOBAL.2.159454
Element CodePDACA0E010
Record TypeSPECIES
ClassificationSpecies
Classification StatusStandard
Name CategoryVascular Plant
IUCNLeast concern
Endemicoccurs (regularly, as a native taxon) in multiple nations
KingdomPlantae
PhylumAnthophyta
ClassDicotyledoneae
OrderScrophulariales
FamilyAcanthaceae
GenusJusticia
Other Common Names
American Water-willow (EN) American water-willow (EN) Carmantine d'Amérique; Justicia d'Amérique (FR)
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 Date2024-05-28
Change Date1985-10-11
Edition Date2024-05-28
Edition AuthorsJean Gagnon (1996), rev. C. Nordman (2024).
Threat ImpactLow
Range Extent>2,500,000 square km (greater than 1,000,000 square miles)
Number of Occurrences> 300
Rank Reasons
Common Water-willow (Justicia americana) occurs in eastern North America in northeastern Mexico, eastern United States from Texas and northern Florida to Michigan and New York, and in southeastern Canada. It is estimated that there are more than 300 (about 700) occurrences rangewide. It is threatened by the impoundment of rivers and creeks as a result of dam construction.
Range Extent Comments
Common Water-willow (Justicia americana) occurs in eastern North America in northeastern Mexico (in Chihuahua and Coahuila), eastern United States from Texas and northern Florida to Michigan and New York, and in southeastern Canada in southern Ontario and southern Quebec. Range extent was estimated to be 2.7 million square kilometers, using herbarium specimens and photo-based observations documented between 1993 and 2024 (GBIF 2024, iNaturalist 2024, Villaseñor 2016, Weakley and Southeastern Flora Team 2023).
Occurrences Comments
By applying a 1 km separation distance to herbarium records and photo-based observations documented between 1993 and 2024, it is estimated that there are more than 300 (about 700) occurrences rangewide (GBIF 2024, iNaturalist 2024).
Threat Impact Comments
Common Water-willow (Justicia americana) is threatened by the impoundment of rivers and creeks as a result of dam construction.
Ecology & Habitat

Habitat

Common Water-willow (Justicia americana) occurs in shallow water of shoals or riffle areas of moderate gradient rocky river and stream beds. It is an obligate wetland plant (Weakley and Southeastern Flora Team 2023).
Palustrine Habitats
HERBACEOUS WETLAND
Other Nations (2)
United StatesN5
ProvinceRankNative
IllinoisSNRYes
MichiganS2Yes
GeorgiaS5Yes
TennesseeSNRYes
OklahomaSNRYes
MississippiSNRYes
New JerseyS4Yes
MarylandSNRYes
DelawareSNANo
South CarolinaS4Yes
ArkansasSNRYes
FloridaSNRYes
West VirginiaS5Yes
KansasS4Yes
KentuckyS5Yes
WisconsinSNRYes
New YorkS4Yes
AlabamaSNRYes
North CarolinaS4Yes
IowaS1Yes
LouisianaS2Yes
VermontSXYes
VirginiaS5Yes
IndianaSNRYes
TexasSNRYes
District of ColumbiaSNRYes
MissouriSNRYes
PennsylvaniaS5Yes
OhioSNRYes
CanadaN2
ProvinceRankNative
QuebecS2Yes
OntarioS2Yes
Threat Assessments
ThreatScopeSeverityTiming
7 - Natural system modificationsSmall (1-10%)Serious or 31-70% pop. declineHigh (continuing)
7.2 - Dams & water management/useSmall (1-10%)Serious or 31-70% pop. declineHigh (continuing)

—

Plant Characteristics
DurationPERENNIAL, SUMMER-FLOWERING
Economic Value (Genus)No
Roadless Areas (19)
Alabama (1)
AreaForestAcres
Oakey MountainTalladega National Forest6,129
Arkansas (7)
AreaForestAcres
Bear MountainOuachita National Forest1,910
Clifty CanyonOzark-St. Francis National Forest1,963
Dismal CreekOzark-St. Francis National Forest9,160
East ForkOzark-St. Francis National Forest13,037
Gee CreekOzark-St. Francis National Forest7,957
PenhookOzark-St. Francis National Forest6,566
Richland CreekOzark-St. Francis National Forest571
Missouri (2)
AreaForestAcres
Irish Rare II Study AreaMark Twain National Forest1,226
Spring Creek Rare II Study AreaMark Twain National Forest4,899
North Carolina (1)
AreaForestAcres
Bald MountainPisgah National Forest11,085
Tennessee (1)
AreaForestAcres
Devil's BackboneCherokee National Forest4,287
Virginia (5)
AreaForestAcres
Beards MountainGeorge Washington National Forest7,505
North MountainJefferson National Forest8,377
Northern MassanuttenGeorge Washington National Forest9,444
Southern MassanuttenGeorge Washington National Forest11,985
Three SistersGeorge Washington National Forest8,149
West Virginia (2)
AreaForestAcres
Marlin MountainMonongahela National Forest9,344
Middle MountainMonongahela National Forest19,020
References (5)
  1. Global Biodiversity Information Facility (GBIF). 2024. Global Biodiversity Information Facility (GBIF) data portal. Online. Available: https://www.gbif.org/ (accessed 2024).
  2. iNaturalist. 2024. Online. Available: https://www.inaturalist.org (accessed 2024).
  3. 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.
  4. Villaseñor, J.L. 2016. Checklist of the native vascular plants of Mexico. Revista Mexicana de Biodiversidad 87: 559-902.
  5. Weakley, A.S., and Southeastern Flora Team. 2023. Flora of the southeastern United States. Edition of April 14, 2023. University of North Carolina Herbarium (NCU), North Carolina Botanical Garden, University of North Carolina, Chapel Hill. 2105 pp.