Mesua thwaitesii, is a plant species in the family Calophyllaceae. It is endemic to Sri Lanka, where Sinhalese people called "Diya Nā - දිය නා". The plant is highly valuable as a medicinal plant within the country.
Planch. & Triana
Mesua ferrea is a complex species and has recently been split into several species and varieties. A.J.G.H. Kostermans and Gunatilleke et al. call the tree described in the Wikipedia article Mesua nagassarium. Kostermans lists several subspecies of Mesua nagassarium.
These authors list Mesua ferrea as a separate species that is endemic to Sri Lanka and is a small, 15 meters high tree that grows near streams and in marshes in the Southwest of Sri Lanka, where it is called "Diya Na" in Sinhala, meaning "Water Na Tree". This "Diya Na" is not cultivated. Gunatilleke et al. (p. 139), however, remark in a footnote: "In the most recent revision diya na is named as Mesua thwaitesii and na as Mesua ferrea".
- Bandaranayake, Wickramasinghe M.; Selliah, Sathiaderan S.; Sultanbawa, M.Uvais S.; Games, D.E. (1975). "Xanthones and 4-phenylcoumarins of Mesua thwaitesii". Phytochemistry. 14: 265–269. doi:10.1016/0031-9422(75)85052-7.
- biotik.org database, entry: "Mesua ferrea L. – Clusiaceae".
- A.J.G.H. Kostermans "Clusiaceae (Guttiferae)" in M. D. Dassanayaka and F. R. Fosberg, eds., A Revised Handbook to the Flora of Ceylon, Volume I, New Delhi 1980, pp. 107–110. Ashton M, Gunatilleke S, de Zoysa N, Dassanayake MD, Gunatilleke N, Wijesundera S. A Field Guide to the Common Trees and Shrubs of Sri Lanka. Colombo 1997 p. 140.