Flowering occurs from October to February and is followed by fruit that are woody capsules 2–3.2 mm (0.08–0.1 in) long in small, loose clusters.

[2][3] The species was first formally described in 1987 by Bryan Alwyn Barlow as a subspecies of Melaleuca minutifolia.

The type specimen was collected near Granite Creek, near Mareeba in Far North Queensland and the description was published in Australian Systematic Botany.

[6][7] The specific epithet (monantha) is from the Ancient Greek words μόνος (mónos) meaning “alone", or "single”[8]: 533  and ἄνθος (ánthos) meaning “flower",[8]: 533  referring to the arrangement of the flowers individually rather than in pairs.

[2] Melaleuca monantha occurs in Queensland, mainly between the Palmer River and Mount Sturgeon (near Hughenden) districts.