Spermatophytes (seed plants): Angiosperms (flowering plants): Eudicots: Core Eudicots: Caryophyllales
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.
This plant is a serious weed of natural areas, per Weakley's Flora (2022)
SYNONYMOUS WITH Floristic Synthesis of North America. BONAP (Kartesz, 2021)
SYNONYMOUS WITH Flora of North America
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, 1938)
To see larger pictures, click or hover over the thumbnails.
Richard and Teresa Ware rtw_a_philoxeroides
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 (Miller, Chambliss, & Lowenstein, 2010).
COMPARE aquatic plants
James H. Miller, USDA Forest Service, Bugwood.org bug_1539028
Leaves somewhat succulent, obtuse to rounded at the tip, per Weakley's Flora (2012).
Gary Buckingham, USDA Agricultural Research Service, Bugwood.org bug_4723003
Each flower w 5 minute petals (actually sepals) surrounding yellow anthers, per A Field Guide for the Identification of Invasive Plants in Southern Forests (Miller, Chambliss, & Lowenstein, 2010).
Julia Scher, Federal Noxious Weeds Disseminules, USDA APHIS ITP, Bugwood.org bug_5376307
Nancy Loewenstein, Auburn University, Bugwood.org bug_5471274
Bracts not keeled. Peduncles 1-7cm, from the leaf axils or terminal, per Weakley's Flora (2012).
Floristic Synthesis of North America. BONAP (Kartesz, 2021)
Flora of North America
Manual of the Southeastern Flora (Small, 1933, 1938)
Emergent aquatic (rooted along shoreline, but floating mats can detach); Forb
Habitat: Floating in mats on the surface of the waters of blackwater rivers, sloughs, ditches, ponds, and in very moist soil of ditches and shores, per Weakley's Flora
Non-native: tropical America
Common in Coastal Plain, uncommon in Piedmont, rare in Mountains
CLICK HERE to see a map, notes, and images from Weakley's Flora of the Southeastern US.
Click here to see a map showing all occurrences known to SERNEC, a consortium of southeastern herbaria. (Zoom in to see more detail.)
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
5 stamens, united at base
TO LEARN MORE about this plant, look it up in a good book!
- Field Guide to Aquatic Plants of Alabama (Lovell, 2007) p07
- Guide to the Wildflowers of SC, 1st ed. (Porcher & Rayner, 2001) p374
- Guide to the Wildflowers of SC, 2nd ed. (McMillan, Porcher, Rayner, & White; 2022) p531
- Invasive Plants, Guide to Identification, Impacts and Control (Kaufman & Kaufman, 2007) p422
- A Field Guide for the Identification of Invasive Plants in Southern Forests (Miller, Chambliss, & Lowenstein, 2010) p098
- Invasive Exotic Plants of North Carolina (Smith, 2008) p052
- Wildflowers of the Atlantic Southeast (Cotterman, Waitt, & Weakley, 2019) p210
- Wildflowers of the Carolina Lowcountry (Porcher, 1995) p098
- Wildflowers of Tennessee (Carman, 2005) p052
- Wildflowers of Tennessee, the Ohio Valley, and the Southern Appalachians (Horn, Cathcart, Hemmerly, & Duhl, 2005) p074
If a search such as "Carex leptalea var. leptalea" doesn't deliver the results you want, try "Carex leptalea".
Or, to minimize chances of a misspelling, try just "Carex le".
Less is more: If "pencil flower" doesn't deliver the results you want, try "pencil".