Abstract
Four new species of Medinilla from Borneo, M. campana, M. flammea, M. purpureoviridis and M. rangkong are described and illustrated based on morphological characteristics. Medinilla campana most resembles M. rubicunda but differs from it by having campanulate hypanthium that thickens significantly towards the distal end (vs. cupuliform and not thickened) and the anther has an underdeveloped, obtuse dorsal spur (vs. well-developed, beak-like dorsal spur). Medinilla flammea is similar to M. rubicunda, but differs in having erect to suberect habit (vs. spreading), the inner pair of lateral veins in the lamina diverges from the midrib above the base (vs. veins diverged from the base) and orange to vermilion petals (vs. white). Medinilla purpureoviridis is somewhat similar to M. laxiflora, but it can easily be distinguished from the latter by its 4-merous flowers (vs. 5-merous) and the cymose branching of approximately 3 times (vs. 5 to 9 times). In addition, the hypanthium is distally thickened (vs. not thickened in M. laxiflora). Medinilla rangkong most resembles M. sessiliflora, but differs in its cordate leaf base (vs. acute), the lateral two veins diverging from the base (vs. departing about 5 mm from the base of midvein), and the hypanthium with four minutely apiculate teeth (vs. with four conspicuous, triangular calyx lobes).