Melicytus lanceolatus, commonly called narrow-leaved māhoe or māhoe-wao,[2] is a small tree[3] in the family Violaceae[4] that is endemic to New Zealand.

[5] Melicytus lanceolatus is a small tree that typically appears slender, glabrous,[6] and erect.

[7] Melicytus lanceolatus has the potential to grow up to 5–6 m tall[8] with a trunk 30 cm in diameter.

[9] The vibrant green[10] leaves of M. lanceolatus are simple, alternate,[11] and have a finely serrated margin.

[7] Flowers are small, 5 mm in diameter,[12] and have five erect petals that curve backwards.

[14] Melicytus lanceolatus produces dark purple round berries that are 4–6 mm in diameter.

[15] This species prefers moist, cool areas[11] with high rainfall[3] from lowland up to montane forests.

[16] Since it prefers cool areas, M. lanceolatus has a cold sensitivity of –2.0 °C,[19] but its leaves were found to endure frosts down to –8.3 °C.

[20] Due to its berries, flowers, and foliage, M. lanceolatus has interactions with insects, birds and introduced mammalian species.

[22] The caterpillars of the puriri moth use the tree as a host plant by burrowing into its trunk and eating the callus tissue produced.

Bemisia flocculosa, also known as the Melicytus whitefly, use M. lanceolatus as a host plant by feeding on the underside of its leaves.

[27] Thrips from the family Lathriidae have been caught visiting its flowers,[14] while larvae from the species Hercinothrips bicinctus have been found infesting its leaves.