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
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INVASIVE

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

 

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.

image of Alternanthera philoxeroides, Alligator-weed

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

        

image of Alternanthera philoxeroides, Alligator-weed

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

image of Alternanthera philoxeroides, Alligator-weed

JK Marlow    jkm160914_110

September        

SE-EPPC Aquatic Plant ID Workshop

image of Alternanthera philoxeroides, Alligator-weed

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.

image of Alternanthera philoxeroides, Alligator-weed

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.

image of Alternanthera philoxeroides, Alligator-weed

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

Month Unknown        

image of Alternanthera philoxeroides, Alligator-weed

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

Month Unknown        

image of Alternanthera philoxeroides, Alligator-weed

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

Month Unknown        

image of Alternanthera philoxeroides, Alligator-weed

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.