|Ceylon ironwood in Thelwatta, South-East Sri Lanka.|
Mesua ferrea (Ceylon ironwood, Indian rose chestnut, or Cobra's saffron), is a species in the family Calophyllaceae. This slow-growing tree is named after the heaviness and hardness of its timber. It is widely cultivated as an ornamental due to its graceful shape, grayish-green foliage with a beautiful pink to red flush of drooping young leaves, and large, fragrant white flowers. It is native to wet, tropical parts of Sri Lanka, India, southern Nepal, Burma, Thailand, Indochina, the Philippines, Malaysia and Sumatra, where it grows in evergreen forests, especially in river valleys. In the eastern Himalayas and Western Ghats in India it grows up to altitudes of 1500 meters, while in Sri Lanka up to 1000 meters.
The tree can grow over 30 meters tall, often buttressed at the base with a trunk up to 2 meters in diameter. The bark of younger trees has an ash grey color with flaky peelings, while of old trees the bark is dark ash-grey with a red-brown blaze. It has simple, opposite, narrow, oblong to lanceolate, blue-grey to dark green leaves that are 7–15 cm long and 1.5–3.5 cm wide, with a whitish underside. The emerging young leaves are red to yellowish pink and drooping. The branches are slender, terete and glabrous. The bisexual flowers are 4–7.5 cm in diameter, with four white petals and a center of numerous orange yellow stamens. The fruit is an ovoid to globose capsule with 1 to 2 seeds. 
History of the tree in Sri Lanka
In the dry zone areas of Sri Lanka—where ironwood trees normally do not grow wild, large, old ironwood trees can be seen around the remains of ancient Buddhist monasteries on rocky hills around Dambulla such as Na Uyana Aranya, Namal Uyana, Na-golla Aranya, Pidurangala near Sigiriya, Kaludiya Pokuna near Kandalama, and Ritigala. They are probably the descendants of trees planted as ornamentals in the monasteries in ancient times during the Anuradhapura period. Older trees form suckers or shoots from the base of the trunk, which become new trees when the old trunk falls down; therefore the bases and roots of some ironwood trees in these sites might be very old.
As the English name indicates, the wood of this tree is very heavy, hard and strong. The density is 940 to 1,195 kg/m3 (59 to 75 lb/ft3) at 15% moisture content. The colour is deep dark red. It is hard to saw and is mainly used for railroad ties and heavy structural timber.  In Sri Lanka the pillars of the 14th century Embekke Shrine near Kandy are made of iron tree wood.
The flowers, leaves, seeds and roots have medicinal properties and are used as herbal medicines in India, Malaysia, etc.  and in Nag Champa incence sticks.
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 this Wikipeda 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”.
Kostermans and Gunatilleke et al classify Mesua ferrea in the Clusiaceae family, while in the AgroForestryTree Database it is allocated to the Guttiferae family.
Mesua ferrea has different names in various languages. 
- Assamese : Nahor, Nokte ( নোক্তে)
- Meghalaya (Garo) - Kimde
- Bengali : Nagesar (নাগেশ্বর)
- Hindi : Gajapushpam; Nāg champa (नाग चम्पा), Nāgakesar (नाग केसर)
- Filipino: kaliuas
- Javanese: nagasari
- Kannada : Nagasampige (ನಾಗಸಂಪಿಗೆ)
- Malaysian : penaga
- Malayalam : Nagachampakam; Veila
- Marathi : Nagchafa, Thorla chafa
- Myanmar: Kant Kaw
- Sanskrit : Champeryah; Nāgakesara; Nāgapushpa, Nāga (नाग)
- Sinhala: Nā
- Tamil : Cheru-nagapu; Sirunagappoo; Veilutta-champakam, Tadinangu, Naka
- Telugu : Nagakesara
- Thai: bunnak
- Urdu: Narmishka (नर्मिश्क)
- AgroForestryTree Database, entry: “Mesua ferrea”. “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.
- AgroForestryTree Database, entry: ““Mesua ferrea”. “biotik.org Database, entry “Mesua ferrea L. – Clusiaceae”
- Bhikkhu Nyanatusita, Forest Monasteries and Meditation Centres in Sri Lanka
- AgroForestryTree Database, entry: Mesua ferrea
- Sri Lanka: Embekke
- AgroForestryTree Database, entry: “Mesua ferrea”. biotik.org database, entry: “Mesua ferrea L. – Clusiaceae”. Flowers of India database, entry: “Nag Kesar”
- 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.
- Mesua ferrea, Dr. K.M. Nadkarni's Indian Materia Medica, by A.K. Nadkarni, Popular Prakashan, Bombay, 1976, pp: 792-4. “Nag Kesar” in the Flowers of India database. AgroForestryTree Database, entry: “Mesua ferrea”.
|Wikimedia Commons has media related to Mesua ferrea.|
- Caldecott, Todd (2006). Ayurveda: The Divine Science of Life. Elsevier/Mosby. ISBN 0-7234-3410-7. Contains a detailed monograph on Mesua ferrea (Nagakeshara) as well as a discussion of health benefits and usage in clinical practice. Available online at http://www.toddcaldecott.com/index.php/herbs/learning-herbs/312-nagakeshara
- Sriracha College: Mesua ferrea (in Thai; numerous photos)[dead link]
- Himalaya Health Care: Mesua ferrea factsheet