Native & Naturalized Plants of the Carolinas & Georgia


2937

Emergent aquatic (rooted along shoreline, but floating mats can detach); Forb
Perennial

Non-native: Tropical America
Documented growing wild in GA NC SC

Common. A serious weed of natural areas

Look for it floating in mats on the surface of the waters of blackwater rivers, sloughs, ditches, ponds, and in very moist soils of ditches & shores, per Weakley's Flora

map
To see a detailed map, click here


INVASIVE

This plant is causing problems in natural areas outside its native range, according to authorities such as:

Alabama Invasive Plant Council, 2012
Georgia Exotic Pest Plant Council, 2006
Kentucky Exotic Pest Plant Council, 2013
Mid-Atlantic Exotic Pest Plant Council
NC Department of Transportation
SC Department of Natural Resources Aquatic Nuisance Species List, 2003
SC List of Regulated Pest Plant Species, 2017
Tennessee Exotic Pest Plant Council, 2009
US Forest Service Southern Research Station
Virginia Department of Conservation and Recreation, 2014

 

Aquatic ...Wet

LEAVES:
Simple
Opposite

FLOWER:
Spring/Summer/Fall
White
Bisexual
5 sepals
Petals absent
5 stamens, united at base

FRUIT:
Spring/Summer/Fall
Utricle

 

TO LEARN MORE about this plant, look it up in a good book!



Spermatophytes (seed plants): Angiosperms (flowering plants): Eudicots: Core Eudicots: Caryophyllales

WEAKLEY'S FLORA (11/30/12):
Alternanthera philoxeroides   FAMILY Amaranthaceae

SYNONYMOUS WITH PLANTS NATIONAL DATABASE:
Alternanthera philoxeroides   FAMILY Amaranthaceae

SYNONYMOUS WITH VASCULAR FLORA OF THE CAROLINAS (1968) 066-01-002:
Alternanthera philoxeroides   FAMILY Amaranthaceae

SYNONYMOUS WITH Manual of the Southeastern Flora (Small, 1933)
Achyranthes philoxeroides

 

COMMON NAME:
Alligator-weed


Click or hover over the thumbnails to see larger pictures.

picture of Alternanthera philoxeroides, image of Alternanthera philoxeroides

USDA-NRCS PLANTS Database / USDA Wetland flora: Field office illustrated guide    pnd_alph_003_lvd

        

picture of Alternanthera philoxeroides, image of Alternanthera philoxeroides

Richard and Teresa Ware    rtw_a_philoxeroides

June        

Small, white, rounded cloverlike clusters of tiny flowers are 0.5-0.7" wide, per A Field Guide for the Identification of Invasive Plants in Southern Forests.


click here to see other plants that look similar to this COMPARE aquatic plants

picture of Alternanthera philoxeroides, image of Alternanthera philoxeroides

JK Marlow    jkm160914_110

September        

SE-EPPC Aquatic Plant ID Workshop

picture of Alternanthera philoxeroides, image of Alternanthera philoxeroides

James H. Miller, USDA Forest Service, Bugwood.org    bug_1539028

Month Unknown        

Leaves somewhat succulent, obtuse to rounded at the tip, per Weakley's Flora.

picture of Alternanthera philoxeroides, image of Alternanthera philoxeroides

Gary Buckingham, USDA Agricultural Research Service, Bugwood.org    bug_4723003

Month Unknown        

Each flower w 5 minute petals (actually sepals) surrounding yellow anthers, per A Field Guide for the Identification of Invasive Plants in Southern Forests.

picture of Alternanthera philoxeroides, image of Alternanthera philoxeroides

Julia Scher, Federal Noxious Weeds Disseminules, USDA APHIS ITP, Bugwood.org    bug_5376307

Month Unknown        

picture of Alternanthera philoxeroides, image of Alternanthera philoxeroides

James H. Miller, USDA Forest Service, Bugwood.org    bug_5379494

Month Unknown        

picture of Alternanthera philoxeroides, image of Alternanthera philoxeroides

James H. Miller, USDA Forest Service, Bugwood.org    bug_5422002

Month Unknown        

picture of Alternanthera philoxeroides, image of Alternanthera philoxeroides

Nancy Loewenstein, Auburn University, Bugwood.org    bug_5471274

Month Unknown        

Bracts not keeled. Peduncles 1-7cm, from the leaf axils or terminal, per Weakley's Flora.