Mitrephora heyneana is a species of plant in the family Annonaceae. It is native to India and Sri Lanka. Joseph Dalton Hooker and Thomas Thomson, the British botanists who first formally described the species under the basionym Orophea heyneana, named it after Benjamin Heyne a German botanist who collected and described many plant species from India.
It is a tree reaching 12 meters in height. Its leathery, oval to lance-shaped leaves are 3âÂÂ11.5 by 2âÂÂ4.5 centimeters with pointed or rounded bases and pointed to tapering tips. The upper side of the leaves are matt and hairless, while the undersides are covered in sparse, fine hairs. The leaves have 6âÂÂ10 pairs of secondary veins emanating from their midribs. Its petioles are 3âÂÂ7 by 1.2 millimeters and covered in sparse, fine hairs. The flowers are on fleshy, densely hairy pedicels that are 2.5-5 by 0.5âÂÂ0.9 millimeters. The pedicels have an oval, basal bract that is 1 by 1 millimeters, and another upper bract that is 1-1.5 by 1âÂÂ2 millimeters. Its flowers have 3 oval sepals that are 1.5âÂÂ2 by 2-2.5 millimeters. The sepals are covered in dense, brown hairs on their outer surface and sparse hairs on their inner surface. Its 6 petals are arranged in two rows of 3. The yellow, oval to lance-shaped, outer petals are 7âÂÂ14 by 2.5âÂÂ6 millimeters and come to a point at their tips. The outer surface of the outer petals are covered in dense, brown, fine hairs while the inner surface is sparsely hairy. The margins of the outer petals are slightly wavy when mature. The inner petals are yellow with red to purple stripes. The inner petals are 6.5âÂÂ8.5 by 4.5âÂÂ6.5 millimeters. The inner petals have dense, fine hairs on their outer surface. The inner surface of inner petals is covered in glandular hairs that become longer at the tip and cause the petals to interlock to form a dome. Its flowers have stamen that are 0.4âÂÂ0.7 by 0.4âÂÂ0.6 millimeters. Its flowers have 9âÂÂ10 carpels that are 0.9âÂÂ1.4 by 0.4âÂÂ0.5 millimeters. The carpels have 4âÂÂ6 ovules. Its fruit occur in clusters of 4âÂÂ9 on pedicels that are 3âÂÂ7.5 by 0.5âÂÂ1.5 millimeters and covered in sparse, fine hairs. The smooth, densely hairy, oval fruit are 14âÂÂ12 by 2.5âÂÂ9 millimeters with flat tips. The fruit are attached to the pedicel by stipes that are 1âÂÂ2 by 1-1.5 millimeters and covered in dense, brown, fine hairs. Each fruit has 2âÂÂ4 seeds that are 8.5âÂÂ10 by 7âÂÂ9 millimeters.
The pollen of M. heyneana is shed as permanent tetrads. Pollination is believed to be assisted by beetles in the Nitidulidae family.
It has been observed growing in rocky forests, at elevations of 200 to 450 meters.
The bioactive molecule betulin extracted from its bark has been shown to inhibit the growth of cultured human tumor cells.