Inflorescence loose, 40-90 cm long, consisting of 4-8 distant fascicles of branches; Stamens in both flowers 6;
Asia-Tropical: Borneo present (Sarawak present), E. Borneo present, Kelindjau River region present, Lobok Pasir present, Mt Kenepai present, Telok Asam present, W. Borneo present, bank of Sendabai lakes present
Malesia: Borneo (E. Borneo, Kelindjau River region; Sarawak: Lobok Pasir, Telok Asam; W. Borneo: bank of Sendabai lakes, Mt Kenepai).
In view of the distribution of the other species the occurrence of a Tetraria in the equatorial lowland of Borneo is very surprising. The group of genera to which Tetraria belongs is extremely difficult, and the genera have been circumscribed in very different ways. The subdistichous glumes, the short straight rachilla, the barren lower flower, the number of stamens, the long appendage of the connective, the persistent style-base, the delicate hypogynous bristles, etc., of the Bornean plant compel to inclusion in the genus Tetraria. There are, however, strong affinities to Costularia pilisepala.