Pseuduvaria pamattonis is a species of plant in the family Annonaceae. It is native to Borneo and the Philippines. Friedrich Miquel, the Dutch botanist who first formally described the species using the basionym Orophea pamattonis, named it after a mountain in Borneo called Gunung Pamaton.
It is a tree reaching in height. The young, yellow to gray-brown branches are slightly to densely hairy and also have sparse lenticels. Its egg-shaped to elliptical, slightly leathery to leathery leaves are by centimeters. The leaves have pointed to blunt bases and tapering tips, with the tapering portion 8âÂÂ24 millimeters long. The leaves are hairless on their upper and lower surfaces. The leaves have 10âÂÂ16 pairs of secondary veins emanating from their midribs. Its sparsely to very densely hairy petioles are 4âÂÂ13 by 1âÂÂ2.5 millimeters with a broad groove on their upper side. Its Inflorescences occur in groups of 2âÂÂ7 on branches, and are organized on indistinct peduncles. Each inflorescence has 1âÂÂ2 flowers. Each flower is on a densely hairy pedicel that is 4âÂÂ11 by 0.3âÂÂ0.7 millimeters. The pedicels are organized on a rachis up to 5 millimeters long that have 2 bracts. The pedicels have a medial, sparsely hairy bract that is 0.2âÂÂ1 millimeters long. Its flowers are unisexual. Its flowers have 3 free, oval sepals, that are 0.5âÂÂ1.5 by 0.7âÂÂ2 millimeters. The sepals are hairless on their upper surface, sparsely to densely hairy on their lower surface, and hairy at their margins. Its 6 petals are arranged in two rows of 3. The white to yellow, oval, outer petals are 1âÂÂ2 by 1âÂÂ2 millimeters with hairless upper and densely hairy lower surfaces. The white to yellow, heart-shaped to diamond-shaped, inner petals have a 2âÂÂ7 millimeter long claw at their base and a 4âÂÂ10 by 2âÂÂ5 millimeter blade. The tips of the male flowers have two concave sides while those of the female flowers are pointed. The bases of the male flowers are heart-shaped to flat while those of the female flowers are flat. The inner petals are densely hairy on their upper and lower surfaces. Male flowers have 30âÂÂ45 stamens that are 0.5âÂÂ0.8 by 0.4âÂÂ0.6 millimeters. Female flowers have 6âÂÂ7 carpels that are 1.4âÂÂ1.6 by 0.6âÂÂ0.9 millimeters. Each carpel has 3âÂÂ5 ovules arranged in two rows. The female flowers have up to 6 sterile stamens. The fruit occur in clusters of 1âÂÂ5 on sparsely to densely hairy pedicles that are 9âÂÂ13 by 1âÂÂ2.5 millimeters. The brown, globe-shaped fruit are 12âÂÂ21 by 11âÂÂ18 millimeters. The fruit are smooth, and very densely hairy. Each fruit has 3âÂÂ5 hemispherical to lens-shaped seeds that are 9âÂÂ11.5 by 6.5âÂÂ9 by 2- millimeters. The seeds are wrinkly.
The pollen of P. pamattonis is shed as permanent tetrads.
It has been observed growing in limestone and clay soils in lowland and mountain forests at elevations of .