Exacum caeruleum is a species of a plant in the Gentianaceae family. It is an annual endemic to the island of Socotra in Yemen. Its natural habitat is dense shrubland in the Hajhir Mountains from 900 to 1,250 meters elevation.
Its notable features include:
Flowers: Typically a bluishâÂÂlavender or violet colour, with prominently goldenâÂÂyellow stamens. (Photographs of close relatives show these character traits)
Leaves: Opposite, glossy or semiâÂÂglossy, simple in shape, clustered on stems.
Habit: In its natural habitat, grows in dense shrublands or among rocks and shrub communities at high elevations.
Morphology (genusâÂÂtypical): According to data for the genus Exacum, stems are erect or branched, glabrous, leaves are opposite and the flowers are in cymes (axillary or terminal), the calyx lobed nearly to base, corolla rotate with lobes longer than the tube, 4âÂÂ5 stamens inserted at throat, ovary 2âÂÂlocular, capsule 2âÂÂvalved, seeds many.