Glabrous. Leaves opposite; lamina (in the Malesian region) narrowly ovate to ovate, 9-15 by 2.5-7 cm, shortly cuneate to truncate at the base to a petiole 2-8 mm long, acuminate and acute at the apex, dull on both sides; venation pinnate with the midrib prominent below and the main veins distinct on both sides. Inflorescences at the nodes, a pseudo-umbel of 1 opposite pair of subsessile flowers; axis 1-3 mm long; pedicels 0-1 mm long; central bract orbicular, 2-3 mm long; lateral bracts 2-3 mm long, connate, together almost completely enclosing the ovary.
Asia-Tropical: Malaya (Peninsular Malaysia present); Vietnam (Vietnam present), Mindanao present
Vietnam; Malesia: Peninsular Malaysia, Mindanao. The species area appears to be disjunct.
In the protologue of Loranthus dianthus King cited four collections, which are therefore syntypes. Scortechini 604a, seen by King and bearing an analysis by Gamble, is selected as lectotype of the species name. The holotype of Loranthus subsessilis (PNH) is no longer extant. Isotypes have been seen (US 901951, L); the former is more substantial and is designated lectotype of the species name. Closely related to Macrosolen platyphyllus', for differences see there. Specimens in Peninsular Malaysia and Indochina with leaves truncate to cordate at the base and rounded at the apex, referred to M. krempfii by previous authors, are possibly intergrades between M. dianthus and M. platyphyllus.