Spermatophytes (seed plants): Angiosperms (flowering plants): Eudicots: Core Eudicots: Caryophyllales
WEAKLEY'S FLORA (11/30/12):
Alternanthera philoxeroides
FAMILY
Amaranthaceae
Dig deeper at SERNEC, a consortium of southeastern herbaria.
Check out EDDMapS.org to see where this has been reported.
Read more about Alligator-weed at Vascular Plants of North Carolina.
SYNONYMOUS WITH
PLANTS NATIONAL DATABASE:
Alternanthera philoxeroides
FAMILY
Amaranthaceae
SYNONYMOUS WITH
VASCULAR FLORA OF THE CAROLINAS (Radford, Ahles, & Bell, 1968) 066-01-002:
Alternanthera philoxeroides
FAMILY
Amaranthaceae
SYNONYMOUS WITH
Manual of the Southeastern Flora (Small, 1933)
Achyranthes philoxeroides
COMMON NAME:
Alligator-weed
To see larger pictures, click or hover over the thumbnails.
)
USDA-NRCS PLANTS Database / USDA Wetland flora: Field office illustrated guide pnd_alph_003_lvd
)
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.
COMPARE
aquatic plants
)
JK Marlow jkm160914_110
September
SE-EPPC Aquatic Plant ID Workshop
)
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 (2012).
)
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.
)
Julia Scher, Federal Noxious Weeds Disseminules, USDA APHIS ITP, Bugwood.org bug_5376307
Month Unknown
)
James H. Miller, USDA Forest Service, Bugwood.org bug_5379494
Month Unknown
)
James H. Miller, USDA Forest Service, Bugwood.org bug_5422002
Month Unknown
)
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 (2012).
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 (Radford, Ahles, & Bell, 1968) 066-01-002:
Alternanthera philoxeroides
FAMILY
Amaranthaceae
SYNONYMOUS WITH
Manual of the Southeastern Flora (Small, 1933)
Achyranthes philoxeroides
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
Click here to see a more detailed map from University of North Carolina at Chapel Hill Herbarium,
or click here to see a map from SERNEC, a consortium of southeastern herbaria.
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
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!
- Field Guide to Aquatic Plants of Alabama p07
- Guide to the Wildflowers of SC p374
- Invasive Plants, Guide to Identification, Impacts and Control p422
- A Field Guide for the Identification of Invasive Plants in Southern Forests p098
- Invasive Exotic Plants of North Carolina p052
- Wildflowers of the Atlantic Southeast p210
- Wildflowers of the Carolina Lowcountry p098
- Wildflowers of Tennessee p052
- Wildflowers of Tennessee, the Ohio Valley, and the Southern Appalachians p074