|Specimen in Saint-Paul, Réunion|
Mirasolia diversifolia Hemsl.
Tithonia diversifolia is a species of flowering plant in the Asteraceae family that is commonly known as the tree marigold, Mexican tournesol, Mexican sunflower, Japanese sunflower or Nitobe chrysanthemum. It is native to eastern Mexico and Central America but has a nearly pantropical distribution as an introduced species. Depending on the area they may be either annual or perennial.
Tithonia diversifolia is 2–3 m (6.6–9.8 ft) in height with upright and sometimes ligneous stalks in the form of woody shrubs. The large, showy flowers are yellow to orange colored and 5–15 cms. wide and 10–30 cms. long. Leaves are sub-ovate, serrate, acute, 10 to 40 cms. long, simply or mostly 3-7 lobed, somewhat glandular, and slightly grayish beneath. The seeds are achenes, 4-angled, and 5mm long. The seeds are spread by wind.
Symbolism and uses
- In Japan, towards the end of the Meiji Period, they were imported as ornamental plants although seldom cultivated there. Having a characteristic bitter taste, they were used to induce a fever to help fight poisoning, although not used for direct medicinal purposes. There is also the story of the species being introduced to Japan by Nitobe Inazo, hence its Japanese name, the Nitobe chrysanthemum (ニトベギク; Nitobegiku).
In Sri Lanka, where it is called Naththasooriya, it is an invasive species. It grows along roadsides and other disturbed habits. Spreading by seeds and rapidly reproducing vegitatively it forms dense stands that prevent the growth of native species. 
- "Taxon: Tithonia diversifolia (Hemsl.) A. Gray". Germplasm Resources Information Network. United States Department of Agriculture. 2011-05-09. Retrieved 2011-05-19.
- Lalith Gunasekera, Invasive Plants: A guide to the identification of the most invasive plants of Sri Lanka, Colombo 2009, p.109.
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