Lumnitzera is a small Indo-West Pacific genus of mangrove trees and shrubs in the family Combretaceae (order Myrtales). It contains just two accepted species — Lumnitzera racemosa Willd. and Lumnitzera littorea (Jack) Voigt — along with their natural hybrid, Lumnitzera × rosea C.Presl, which arises where the two species' ranges overlap.
Both species share a similar vegetative appearance: flat, spoon-shaped (spathulate) leaves with notched (emarginate) tips. They are distinguished principally by flower colour: L. racemosa bears white flowers and dominates the western portion of the genus's range, while L. littorea bears red flowers and is more prevalent in the east.
The genus ranges from East Africa across the Indo-West Pacific to Fiji, Tonga, and northern Australia, growing in the mangrove zone along tropical and subtropical coastlines. Within the family Combretaceae, three genera are associated with mangrove habitats — Laguncularia, Conocarpus, and Lumnitzera — but Lumnitzera is the only one restricted to Indo-West Pacific mangroves.
The common name "black mangrove" is sometimes applied to Lumnitzera, though this name is also used for the unrelated genus Avicennia, which can cause confusion.
Etymology
The genus Lumnitzera was named in honour of Stephan Lumnitzer (1750–1806), a German botanist.
Distribution
Lumnitzera occurs in mangrove ecosystems from East Africa eastward through the Indo-West Pacific, including Fiji and Tonga, to northern Australia. L. racemosa predominates in the western part of this range; L. littorea predominates in the east; hybrids (L. × rosea) form where their ranges meet.
Ecology
Lumnitzera species grow as trees or shrubs within tropical and subtropical mangrove communities. Lumnitzera is the sole representative of the family Combretaceae in Indo-West Pacific mangroves, occupying a niche shared elsewhere by related genera such as Laguncularia and Conocarpus in Atlantic mangroves.
