Spermatophytes (seed plants): Angiosperms (flowering plants): Monocots: Alismatales
WEAKLEY'S FLORA OF THE SOUTHEASTERN US (2/10/25):
Hydrilla verticillata ssp. verticillata
FAMILY
Hydrocharitaceae
Go to FSUS key
Dig deeper at SERNEC, a consortium of southeastern herbaria.
Check out EDDMapS.org to see where this has been reported.
Hydrilla is most similar to Egeria, but it possesses prickles along the leaf margins and also on the central leaf vein beneath. Read more at Vascular Plants of North Carolina.
Aquatic weeds can clog irrigation channels and cover lakes, threatening crops and wildlife. Read more -- Outlawed! Federal Noxious Weeds: The Aquatics.
INCLUDED WITHIN
PLANTS NATIONAL DATABASE:
Hydrilla verticillata
FAMILY
Hydrocharitaceae
INCLUDED WITHIN Floristic Synthesis of North America. BONAP (Kartesz, 2021)
Hydrilla verticillata
INCLUDED WITHIN Flora of North America north of Mexico, vol. 22 (2000)
Hydrilla verticillata
INCLUDED WITHIN Aquatic & Wetland Plants of Southeastern US (Godfrey & Wooten, 1979 & 1981)
Hydrilla verticillata
COMMON NAME:
Whorled Hydrilla
To see larger pictures, click or hover over the thumbnails.
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Keith Bradley kab_h_verticillata_74746
June Miami-Dade County FL
South Dade Wetlands
Stems and leaves near the surface look like bottle brushes, per Invasive Plants, Guide to Identification, Impacts and Control (Kaufman & Kaufman, 2007).
COMPARE
aquatic plants
WEAKLEY'S FLORA OF THE SOUTHEASTERN US (2/10/25):
Hydrilla verticillata ssp. verticillata
FAMILY
Hydrocharitaceae
INCLUDED WITHIN
PLANTS NATIONAL DATABASE:
Hydrilla verticillata
FAMILY
Hydrocharitaceae
INCLUDED WITHIN
Floristic Synthesis of North America. BONAP (Kartesz, 2021)
Hydrilla verticillata
INCLUDED WITHIN
Flora of North America north of Mexico, vol. 22
Hydrilla verticillata
INCLUDED WITHIN
Aquatic & Wetland Plants of Southeastern US (Godfrey & Wooten, 1979 & 1981)
Hydrilla verticillata
711
Submersed aquatic (rooted); Forb
Perennial
Dioecious
Habitat: Ponds, lakes, rivers, often locally abundant. This species has become a serious aquatic weed, per Weakley's Flora
Non-native: China & adjacent areas
Common in Coastal Plain (uncommon in Piedmont)
CLICK HERE to see a map, notes, and images from Weakley's Flora of the Southeastern US.
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
- NC Department of Transportation
- SC Department of Natural Resources Aquatic Nuisance Species List, 2003
- SC List of Regulated Pest Plant Species, 2017
- US Fish & Wildlife Service
- USDA Federal Noxious Weeds, 091820
IS THE PLANT "ARMED"?
Leaves have stout sharp teeth on margins and midrib beneath
LEAVES:
Simple
Whorls of 4-8
Margins toothed with stout sharp teeth
FLOWER:
Summer
Whitish sepals & translucent petals in female flowers, male reddish-brown
3 sepals in pistillate flowers
3 petals in pistillate flowers
Flowers solitary on elongate flexuous stalks
FRUIT:
Summer/Fall
Capsule
TO LEARN MORE about this plant, look it up in a good book!
- Field Guide to Aquatic Plants of Alabama (Lovell, 2007) p42
- Invasive Plants, Guide to Identification, Impacts and Control (Kaufman & Kaufman, 2007) p429
- Invasive Exotic Plants of North Carolina (Smith, 2008) p054
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