Pseuduvaria trimera is a species of plant in the family Annonaceae. It is native to China, Myanmar, Thailand, and Vietnam. William Grant Craib, the British botanist who first formally described the species, named it after its fascicles of flowers that often occur in three (Latinized form of Greek , tri-) parts (Latinized form of Greek , -meros).
It is a tree reaching in height. The young, brown branches are densely hairy, but become hairless with maturity. Its egg-shaped to elliptical, slightly leathery leaves are by . The leaves have blunt to wedge-shaped bases and tapering tips, with the tapering portion 4âÂÂ17 millimeters long. The leaves are sparsely hairy on their upper surface and hairless on their lower surface. The leaves have 14âÂÂ18 pairs of secondary veins emanating from their midribs. Its very densely hairy petioles are 4âÂÂ11 by 1.5âÂÂ2.5 millimeters with a broad groove on their upper side. Its Inflorescences occur in groups of 3âÂÂ6 on branches, and are organized on indistinct peduncles. Each inflorescence has up to 1âÂÂ2 flowers. Each flower is on a very densely hairy pedicel that is 10âÂÂ30 by 0.5âÂÂ1.5 millimeters. The pedicels are organized on a rachis up to 5 millimeters long that have 2âÂÂ3 bracts. The pedicels have a medial, very densely hairy bract that is up to 0.5âÂÂ1.2 millimeter long. Its flowers are unisexual. Its flowers have 3 free, oval sepals, that are 1âÂÂ1.5 by 2âÂÂ2.5 millimeters. The sepals are hairless on their upper surface, densely hairy on their lower surface, and hairy at their margins. Its 6 petals are arranged in two rows of 3. The yellow to light green, oval, outer petals are 2âÂÂ3 by 1.5âÂÂ3 millimeters with hairless upper and very densely hairy lower surfaces. The yellow to light green, triangular inner petals have a 2.5âÂÂ5 millimeter long claw at their base and a 5âÂÂ8 by 3âÂÂ3.5 millimeter blade. The inner petals have flat bases and pointed tips. The inner petals are sparsely hairy on their upper surfaces and densely hairy on lower surfaces. The male flowers have 46âÂÂ56 stamens that are 0.6âÂÂ0.8 by 0.5âÂÂ0.8 millimeters. Female flowers have 7âÂÂ14 carpels that are 1.5âÂÂ2 by 0.7âÂÂ1 millimeters. Each carpel has up to 5âÂÂ6 ovules arranged in two rows. The female flowers have 7âÂÂ9 sterile stamen. The fruit occur in clusters of 7âÂÂ8 are organized on indistinct peduncles. The fruit are attached by sparsely nearly hairless pedicles that are 20âÂÂ30 by 2.5âÂÂ3.5 millimeters. The green, globe-shaped fruit are 16âÂÂ22 by 16âÂÂ21 millimeters. The fruit are wrinkly, and densely hairy. Each fruit has up to 6 hemispherical to lens-shaped, wrinkly seeds that are 12.5âÂÂ17 by 7.5âÂÂ9.5 by 4.5âÂÂ7 millimeters. Each seed has a 0.5âÂÂ2 by 0.5âÂÂ1.2 millimeter circular to elliptical hilum. The seeds are arranged in two rows in the fruit.
The pollen of P. trimera is shed as permanent tetrads.
It has been observed growing in evergreen and deciduous forests below limestone mountains at elevations of .
Extracts of bioactive molecules from its tissues have been reported to contain aporphine derivatives with cytoxic activity in tests with culture human cancer cells.