Lasianthus oliganthus is a species of plant in the family Rubiaceae. It is endemic to Sri Lanka.
Acute to obtuse base, pointed apex, 4-5 lateral veins.
Branches slender, slightly rough, adpressed hairs.
Very small, sessile, solitary, or 2 or 3.
Very small, depressed berry, truncate at top.
Rain forest understory of wet zone.