Limnophila aromatica (synonym: Limnophila chinensis var. aromatica; also called rice paddy herb) is a tropical flowering plant in the plantain family, Plantaginaceae. It is native to Southeast Asia, where it flourishes in hot temperatures and grows most often in watery environments, particularly in flooded rice fields. It is called Ngò ôm or ngò om or ngổ in Vietnam and used as an herb and also cultivated for use as an aquarium plant. The plant was introduced to North America in the 1970s due to Vietnamese immigration following the Vietnam War. It is called "roum om" (រំអម) in Khmer or Phnom Penh dialect "ma om" (ម្អម). It is used in all traditional Cambodian soup dishes and most often in Vietnamese cuisine. It can grow in flooded rice paddies during wet season but it grows best on drained