Panikola or Duck lettuce (Ottelia alismoides, family: Hydrocharitaceae) is an annual submerged herb grows in the paddy fields and at the edge of water bodies. The short-stemmed aquatic plant prefers shallow water bodies and can survive in strong light. Its roots along with rhizome are ingrained in soil. It is found in the tropical and subtropical Asia, Africa and Australia.
Other Bangla names: Ram korola, Kaobali, Torukola, Shyamkola, Kuchkolai, Jol-kolosh, Pani-kolosh, Jol-kola.
Leaves grow up with the rise in water level. Size and shape of the leaves are different. They are usually oblong-cordate, slightly clear, fragile, edge undulate. The size of the petiole depends on the level of water too. It generally gets a length of 10-20 cm. Peduncle comes out from the rhizome.
The flower is covered with green spathes in early stage. Mature flower stands erectly on the water. Flower is white or light violet. Sepals 3, petals 3. Flowering occurs in autumn and late autumn in Bangladesh.