Limnophila sessiliflora

Limnophila

Nonnative to FloridaFederal Noxious Weed ListFISC Category 2 Invasive

Species Overview

Limnophila sessiliflora is a freshwater amphibious herb which has two distinctly different forms of leaves, submersed and emersed. It may form dense stands from the bottom to the top of the water. Limnophila sessiliflora and Limnophila indica, both non-native species present in the U.S., are frequently cultured as aquarium plants.

Origin

  • there are about 36 species of Limnophila in the world, including 13 aquatic species
  • Limnophila sessiliflora is native to India, Ceylon and the Philippines
  • is present in the Philippies (Pancho 1976)
  • is present in Japan (Harada 1975; Kunii 1991), and was found in Japan as early as 1932 (Kunii 1991)
  • is a major weed problem in paddy rice fields of India, China, Japan and the Philippines

Non-Native to Florida

Origin: India to Southeast Asia1

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This species appears on the following legally prohibited plant lists

Federal Noxious Weed List Florida Noxious Weed List Florida Prohibited Aquatic Plants List
Yes No Yes

UF-IFAS Assessment of Non-Native Plants in Florida’s Natural Areas

CATEGORY I on the Florida Exotic Pest Plant Council’s (FLEPPC) 2017 List of Invasive Plant Species


Download a recognition card (PDF) from Invasive and Non-native Plants You Should Know2

Download a page (PDF) from Identification and Biology of Nonnative Plants in Florida’s Natural Areas – Second Edition1

LIMNOPHILA SESSILIFLORA (Vahl)
limnophila, ambulia, Asian marshweed
Scrophulariaceae/Figwort Family

pronounced: lim-no-fil-a se-si-li-flo-ra
limne (G.): marsh, swamp
phil (G.): loving
sessil (L.): without a stalk
flora (L.): flower

“marsh loving plant having flowers without stalks”

Species Characteristics

Original description

  • dicot
  • rooted in the hydro-soil
  • stems grow to 12 feet, with several inches erectly emersed
  • leaves in whorls along the stem
  • leaves polymorphic, submersed and emersed; mostly to 1.5 in. (5-40 mm) long
  • emersed leaves dark green, more-or-less lance-shaped; in whorls of 5-8 leaves about the stem (also reported as 4-12, Gilbert 1984); margins appear to be torn irregularly (crenate-serrate to variously lacerate)
  • submersed leaves are finely divided and feathery, segments opposite; ovate, elliptic to broadly lanceolate; in whorls of 6-10 leaves (and more) about the stem
  • flowering April through November (Japan, Kunii 1991), and July through November (in north Florida and Texas, Correll & Correll 1975)
  • flowers small, sessile (without stalks); solitary in leaf axils (angle where leaf meets the stem) in the apical (uppermost) parts of the stems, above the water (aerial); corolla (petals) 5-10 mm long, blue, violet, pink or lavender, upper lip white or pink with 2 blue dots, 3-lobed, lobes ovate; calyx 4-7 mm long, hairy (pubescent); pedicels stout (not slender)
  • rooting at stem nodes, with copious roots (Sculthorpe 1967)
  • fruit are capsules, ellipsoid, 3.5-5.5 mm long, green-brown when submersed, dark brown when emersed

Impacts

  • Limnophila sessiliflora is fast-growing and able to regrow from fragments
  • able to shade out and thus outcompete totally submersed species
  • limnophila clogs irrigation and flood-control canals, and pumping and power stations
  • this species is a major weed problem in paddy rice fields of India, China, Japan and the Philippines (Misra 1975; Takematsu 1976)

Control Methods

Preventive Measures

First, clean your boat before you leave the ramp! Transporting plant fragments on boats, trailers, and in livewells is the main introduction route to new lakes and rivers. But, there’s plenty more you can do to help.

Cultural/Physical
Mechanical

The action of mechanical harvestors and chopping machines serves to help spread this invasive plant, which re-grows from leaf fragments.

Biological

The herbivorous (plant-eating) biological control fish, the Chinese grass carp, does not eat Limnophila sessiliflora

Chemical

Registered aquatic herbicides provide very limited control of this species (Mahler 1980); however, high levels of 2-4,D reportedly kills this plant (Mahler 1980); otherwise, there is almost no literature describing possible control methods for this plant.