Limnophila aromatica is a tropical flowering plant

Flowering plant

The flowering plants , also known as Angiospermae or Magnoliophyta, are the most diverse group of land plants. Angiosperms are seed-producing plants like the gymnosperms and can be distinguished from the gymnosperms by a series of synapomorphies...

 in the plantain

Plantago

Plantago is a genus of about 200 species of small, inconspicuous plants commonly called plantains. They share this name with the very dissimilar plantain, a kind of banana. Most are herbaceous plants, though a few are subshrubs growing to 60 cm tall. The leaves are sessile, but have a narrow...

 family, Plantaginaceae

Plantaginaceae

Plantaginaceae Juss. or plantain family, are a family of flowering plants in the order Lamiales. The type genus is Plantago L..In older classifications it used to be the only family of the order Plantaginales, but numerous phylogenetic studies, summarized by the Angiosperm Phylogeny Group, have...

. It is native to Southeast Asia

Southeast Asia

Southeast Asia, South-East Asia, South East Asia or Southeastern Asia is a subregion of Asia, consisting of the countries that are geographically south of China, east of India, west of New Guinea and north of Australia. The region lies on the intersection of geological plates, with heavy seismic...

, where it flourishes in hot temperatures and grows most often in watery environments, particularly in flooded rice fields. It is called ngò om or ngổ in Vietnam

Vietnam

Vietnam – sometimes spelled Viet Nam , officially the Socialist Republic of Vietnam – is the easternmost country on the Indochina Peninsula in Southeast Asia. It is bordered by China to the north, Laos to the northwest, Cambodia to the southwest, and the South China Sea –...

 and used as an herb and also cultivated for use as an aquarium

Aquarium

An aquarium is a vivarium consisting of at least one transparent side in which water-dwelling plants or animals are kept. Fishkeepers use aquaria to keep fish, invertebrates, amphibians, marine mammals, turtles, and aquatic plants...

 plant. The plant was introduced to North America in the 1970s due to Vietnamese immigration following the Vietnam War

Vietnam War

The Vietnam War was a Cold War-era military conflict that occurred in Vietnam, Laos, and Cambodia from 1 November 1955 to the fall of Saigon on 30 April 1975. This war followed the First Indochina War and was fought between North Vietnam, supported by its communist allies, and the government of...

. It is called "roum om" in Khmer or Phnom Penh dialect "ma om". It is used in all traditional Cambodian soup dishes. It can grow in flooded rice paddies during wet season

Wet season

The the wet season, or rainy season, is the time of year, covering one or more months, when most of the average annual rainfall in a region occurs. The term green season is also sometimes used as a euphemism by tourist authorities. Areas with wet seasons are dispersed across portions of the...

 but it grows best on drained but still wet sandy soil of harvested rice paddies for a few months after the rainy season ended. After the rain stops at the end of monsoon season in Cambodia, on the right soil, the herb grows everywhere like wildfire. It dies out soon after it flowers. Rural Cambodians often harvest them and put them on the roof of their houses to dry for later use.

Taxonomy

L. aromatica was formerly classified as a member of the figwort family, Scrophulariaceae

Scrophulariaceae

Scrophulariaceae, the figwort family, are a family of flowering plants. The plants are annual or perennial herbs with flowers with bilateral or rarely radial symmetry. Members of the Scrophulariaceae have a cosmopolitan distribution, with the majority found in temperate areas, including...

. L. aromaticoides is actually not a distinct species, but a variety of L. aromatica.

Culinary use

L. aromatica has a flavor and aroma reminiscent of both lemon

Lemon

The lemon is both a small evergreen tree native to Asia, and the tree's ellipsoidal yellow fruit. The fruit is used for culinary and non-culinary purposes throughout the world – primarily for its juice, though the pulp and rind are also used, mainly in cooking and baking...

 and cumin

Cumin

Cumin is a flowering plant in the family Apiaceae, native from the east Mediterranean to India. Its seeds are used in the cuisines of many different cultures, in both whole and ground form.-Etymology:...

. It is used most often in Vietnamese cuisine

Cuisine of Vietnam

Vietnamese cuisine is a style of cooking derived from Vietnam. Fish sauce and paste, soy paste, rice, fresh herbs, fruits and vegetables are commonly used. Vietnamese recipes utilize a diverse range of herbs, including lemongrass, mint, Vietnamese mint, long coriander and Thai basil leaves...

, where it is called ngò om. It is an ingredient in canh chua

Canh chua

Canh chua is a sour soup indigenous to the Mekong Delta region of southern Vietnam. It is typically made with fish from the Mekong River Delta, pineapple, tomatoes , and bean sprouts, in a tamarind-flavored broth...

, a sweet and sour seafood soup which also includes tamarind

Tamarind

Tamarind is a tree in the family Fabaceae. The genus Tamarindus is monotypic .-Origin:...

,not to be confused with ngò gai

Eryngium foetidum

Eryngium foetidum is a tropical perennial and annual herb in the family Apiaceae. It is native to Mexico and South America but is cultivated worldwide...

which is also added as an accompaniment to the noodle soup called phở

PHO

PHO may refer to:* Primary Health Organisation* Potentially hazardous object, an asteroid or comet that could potentially collide with Earth...

.
In Thai cuisine it is known as phak kayang and is also used to make om.

External links

• Rice Paddy Herb (Limnophila aromatica [Lomk. Merril) page] from Gernot Katzer's Spice Pages