Couroupita guianensis, whose common names include Ayahuma and the Cannonball Tree, is an evergreen tree allied to the Brazil nut (Bertholletia excelsa), and is native to tropical northern South America; and to the southern Caribbean. In India it has been growing for the past two or three thousand years at least, as attested by textual records; hence it is possible that it is native to India also. It’s rare, but also found in Bangladesh. It is known as নাগকেশর(Nagakeshar) or নাগালিংগম(Nagalingam) in Bengali.
It’s part of the family Lecythidaceae and grows up to 25 m (82 ft) in height. The “Cannonball Tree” is so called because of its brown cannon-ball-like fruits. The majority of these trees outside their natural environment have been planted as a botanical curiosity, as they grow very large, distinctive flowers. Its flowers are orange, scarlet and pink in color, and form large bunches measuring up to 3m in length. They produce large spherical and woody fruits ranging from 15 to 24 cm in diameter, containing up to 200 or 300 seeds a piece.
The trees are grown extensively in Shiva temples in India. In Hindi it is called Shiv Kamal and also known as “Kailaspati”. It is called the Nagalingam tree in Tamil. The flowers are called Shivalingaflowers in Hindi; Nagalinga Pushpa in Kannada; Nagamalli flowers or Mallikarjuna flowers in Telugu. Hindus revere it as a sacred tree because the petals of the flower resemble the hood of theNaga, a sacred snake, protecting a Shiva Lingam, the stigma.
Tree referred by Sham Manchekar. Detailed information from Wikipedia.