Barry Conn (NSW) & Kipiro Damas (LAE).
Copyright held by the authors, Royal Botanic Gardens and Domain Trust, and Papua New Guinea National Herbarium

Avicennia alba Blume

Bijdragen tot de flora van Nederlansch Indië Vol. 14: 821 (1826)

Other Literature: N.C. Duke, Australian Systematic Botany Vol. 4: 307-309 (1991) Fig. 5.

Field Characters: Small trees often about 10 m high, frequently a shrub or large trees up to 25 m high. Bole cylindrical; straight; buttresses absent; spines absent; aerial roots rarely present just above base; pneumatophores about 20 cm high, 5-10 mm wide near apex or absent; stilt roots absent. Bark black or dark brown, rough or smooth, pustular warty or often fissured forming short longitudiinal fisures and very small scales; lenticels elongated vertically; subrhytidome pale yellow cream-coloured or green; bark thickness <25 mm thick; blaze consisting of one layer; faintly to non-aromatic; outer blaze pale yellow or white, markings absent, smooth spongy; inner blaze white or pale yellow, markings absent, smooth spongy; exudate absent. Terminal buds not enclosed by leaves; complex hairs absent; stinging hairs absent; mature twig without hairs.

Leaves: Spaced along branches <internodes readily visible>. Leaves opposite, simple; petiole present 4-12(-21) mm long, not winged, attached to base of leaf blade <not peltate>, slightly swollen <at tip, or base, or both> at base; lamina broadest at or near middle or slightly broadest above middle, 7.5-9.0 (-11.0) cm long, 3.0-4.0 (-6.0) cm wide; lamina symmetric, margin entire, not dissected or lobed, apex obtuse, venation pinnate <secondary veins arising from the midrib along its length>, secondary veins open <spaced far apart to easily see tertiary veins>, not prominent, but visible, intramarginal veins absent; lower surface grey silvery green or green, upper surface glossy dark green, hairs often present or absent, sparse minutely hairy on lower leaf surface; oil dots absent; domatia absent; stipules absent.

Flowers: Inflorescence terminal <at branch ends> or axillary <from between a leaf and branch> in distal axils. Flowers on a branched axis flowers in spike-like clusters; flowers bisexual, not stalked aromatic, with many planes of symmetry <actinomorphic>, 3.0-5.0 mm long, small (< or =10 mm diam.) 3-4 mm diam.; perianth present, with distinct sepals and petals, orange or yellow; inner perianth 4 sometimes (-6), some or partly joined lobes 2.5-5 mm long; stamens 4 sometimes (-6), filaments present, free of each other, joined to perianth <epipetalous/episepalous> ovary superior <seated above petals and sepals; hypogenous>, carpels joined (when more than one) <syncarpous>, locules 1; styles absent (by misinterpretation) or solitary <including joined together> minute, barely extended from ovary, 1.

Fruits: Fruits arranged on branched axis. Fruit 21-33 mm long, 8.0-15.0 mm diam., fruit greenish grey dull or pale green, not spiny, non-fleshy, simple, dehiscent, capsule. Seeds 1 (-2) (seedlings developing on plant), not winged, as wide as long.

Distribution: Milne Bay, Morobe, Manus, Northern, Papuan Islands & Madang.

Botanical records in PNGplants database Map details

Notes: The seedling (radicle) of this species is about 9 mm long and is mostly glabrous with a dense hairy collar about 2 mm wide, with hooked hairs.
Previously placed in the Verbenaceae and more recently in its own family, the Avicenniaceae.