Dillenia is a genus of evergreen or semi-evergreen trees and shrubs in the flowering plant family Dilleniaceae, placed in the order Dilleniales. The genus comprises roughly 60 accepted species distributed across tropical and subtropical regions of southern Asia, Australasia, and the Indian Ocean islands.
Plants in the genus share a distinctive and uniform floral architecture: flowers are solitary or borne in terminal racemes, each with five sepals, five petals, and a dense mass of numerous stamens — up to 900 in Dillenia ovalifolia. The gynoecium consists of a cluster of five to twenty carpels. In several species, including Dillenia indica and Dillenia megalantha, individual flowers can reach 20 cm (nearly 8 inches) in diameter, making them among the largest flowers produced by plants in this family. The flowers bear a superficial resemblance to those of Magnolia, though the two genera are not closely related.
Leaves are simple and spirally arranged. They tend to be notably large; Dillenia reticulata produces leaves that can reach 1.27 m (over 4 feet) in length and 41 cm in width.
The genus is named in honour of the German botanist Johann Jacob Dillenius (1684–1747), a professor at Oxford and one of the foremost botanists of the eighteenth century.
Etymology
The genus name Dillenia honours Johann Jacob Dillenius (1684–1747), a German-born botanist who became the first Sherardian Professor of Botany at Oxford. The name was assigned in recognition of his contributions to systematic botany.
Distribution
Dillenia is native to tropical and subtropical regions spanning southern Asia (including the Indian subcontinent and Southeast Asia), Australasia, and islands of the Indian Ocean. The genus is centred on tropical Asia, with species occurring across the Indo-Pacific region from India and Sri Lanka through Southeast Asia to New Guinea and northern Australia.
