- Mostly submerged, inconspicuously hairy when young.
- Strongly dimorphic, with emergent leaves only present at flowering. Submerged leaves opposite, petiolate, to 4 cm long and broad, fan-shaped, palmately divided into 5-7 parts, each of these further divided into narrow, threadlike segments. Emergent leaves alternate, long-petiolate, peltate, with blades to 2 cm long, entire, roughly oblong but often shallowly notched.
- Stalked, held just above the water, the stalk bending to become submerged as the fruits develop. Sepals 3, 5-10 mm long, petaloid, elliptic to obovate, white. Petals 3, 5-10 mm long, elliptic to obovate, sagittate toward the base and thus appearing short-stalked, white with the basal auricles each with a yellow nectary. Stamens 6. Pistils 2-4, the stigma capitate.
- May - September.
- Submerged aquatic in ponds, sloughs, swamps, ditches.
- Native to the U.S.
- This attractive aquatic species can produce large numbers of small white flowers at the surface of still waters, while most of the plant remains submerged. The plant is easily identified by its flowers and the dimorphic leaves. The sepals and petals are similar, collectively forming a six parted perianth.
provides good cover for fish and other aquatic invertebrates, and is commonly grown as an ornamental for aquarium use. This use has led to its accidental escape and introduction at some sites beyond its natural range.
could be confused with species of
, which also have dissected, fan-shaped leaves. However, the leaf arrangement on these latter species is alternate.
Missouri populations of this species are assignable to var.
Photographs taken at Duck Creek Conservation Area, 8-26-2015 (SRTurner).
This plant is listed by the U.S. federal government or a state. Common names are from state and federal lists. Click on a place name to get a complete noxious weed list for that location, or click here for a composite list of all
Federal and State Noxious Weeds
Q list (temporary "A" list noxious weed, pending final determination )
Class B noxious weed
Wetland and aquatic weed quarantine
U.S. Weed Information
This plant can be weedy or invasive according to the authoritative sources noted below.This plant may be known by one or more common names in different places, and some are listed above. Click on an acronym to view each weed list, or click here for a composite list of
Weeds of the U.S.
A. Gray, Ann. Lyceum Nat. Hist. New York. 4: 47. 1837.
R. M. Harper;
(R. M. Harper) Fassett
Submersed leaves: petiole to 4 cm; leaf blade 1-3.5 × 1.5-5.5 cm, terminal segments 3-200, linear to slightly spatulate, to 1.8 mm wide. Floating leaves: blade 0.6-3 cm × 1-4 mm, margins entire or notched to sagittate at base. Flowers 6-15 mm diam.; sepals white to purplish [yellow] or with purple-tinged margins, 5-12 × 2-7 mm; petals colored as sepals but with proximal, yellow, nectar-bearing auricles, 4-12 × 2-5 mm, apex broadly obtuse or notched; stamens 3-6, mostly 6; pistils 2-4, mostly 3, divergent at maturity; ovules 3. Fruits 4-7 mm. Seeds 1-3, 1.5-3 × 1-1.5 mm, tubercles in 4 longitudinal rows. 2 n = ca. 78, ca. 104.
Flowering late spring-early fall, earlier and later further south. Acidic to alkaline ponds, lakes, pools in marshes, rivers, streams, ditches, canals, and reservoirs; 0-300 m; Ont.; Ala., Ark., Conn., D.C., Fla., Ga., Ill., Ind., Ky., La., Md., Mass., Mich., Miss., Mo., N.H., N.J., N.Y., N.C., Ohio, Okla., Oreg., Pa., R.I., S.C., Tenn., Tex., Va.; s South America.
Cabomba caroliniana , an important aquarium plant, is introduced in Oregon and probably in the northern part of its range where it is uncommon in several states. Formerly known from Kansas, it is thought to be extirpated there now. Although Delaware and West Virginia lie within the mapped area, I know of no collections from those states. In New England and parts of southeast United States, it is sometimes an aggressive weed. In parts of the southeastern United States, plants with purple-tinted flowers, possibly a response to some environmental factor, have been treated as Cabomba caroliniana var. pulcherrima . South American plants with yellow flowers have been called C . caroliniana var. flavida O/rgaard.
The submersed leaves of Cabomba caroliniana are similar in form to those of Limnophila (Scrophulariaceae; introduced in southeastern United States). The latter has whorled leaves in contrast to the opposite leaves of Cabomba .
Schneider, E. L. and J. M. Jeter. 1982. Morphological studies of the Nymphaeaceae. XII. The floral biology of
. Amer. J. Bot. 69: 1410-1419.