Avicennia L.

Flora Zambesiaca. Vol 8, Pt 7. Avicenniaceae, R. Fernandes. Nesogenaceae, M.A. Diniz. Verbenaceae, R. Fernandes. Lamiaceae, R. Fernandes. 2005.

Morphology General

Characters as for the family.

Distribution

A widespread genus with 3–6(12) species (fide Verdcourt ) tropical Africa, Asia, Oceania and America.  It is represented by a single species along the east coast of Africa, including the Seychelles, the Comoros, the Mozambique Channel Islands, Mada

Note

Characters as for the family.

Verbenaceae, B. Verdcourt. Flora of Tropical East Africa. 1992

Morphology General Habit

Shrubs or small trees of the mangrove zone; pneumatophores present; nodes swollen

Morphology Leaves

Leaves simple, lanceolate to elliptic, decussate, coriaceous, entire; stipules absent

Morphology Reproductive morphology Flowers

Flowers sessile, yellow to orange in terminal and axillary often capitate cymes, regular, subtended by an involucre of 1 scale-like bract and 2 scale-like bracteoles

Morphology Reproductive morphology Flowers Calyx

Calyx deeply 5-lobed; lobes ovate, imbricate

Morphology Reproductive morphology Flowers Corolla

Corolla-tube shortly campanulate; lobes 4, ovate

Morphology Reproductive morphology Flowers Androecium Stamens

Stamens inserted at the throat, equal or slightly didynamous, alternating with the lobes

Morphology Reproductive morphology Flowers Gynoecium Pistil

Ovary with free central placentation; ovules 4, pendulous; style shortly divided

Morphology Reproductive morphology Fruits

Capsule broadly ellipsoid, compressed, opening by 2(–4) thick valves; usually only 1 erect seed; embryo with large longitudinally folded cotyledons and villous radicle, viviparous; endosperm fleshy.

M. Thulin et al. Flora of Somalia Vol. 1-4 [updated 2008] https://plants.jstor.org/collection/FLOS

Morphology General Habit

Trees and shrubs, with erect aerial roots (pneumatophores); young stems 4-angled

Morphology Leaves

Leaves opposite, simple, without stipules

Morphology Reproductive morphology Flowers

Flowers bisexual, regular, in terminal and axillary dense cymes, each flower subtended by an involucre of a scale-like bract and 2 bracteoles

Morphology Reproductive morphology Flowers Calyx

Calyx deeply 5-lobed, with imbricate lobes

Morphology Reproductive morphology Flowers Corolla

Corolla-tube short, lobes 4

Morphology Reproductive morphology Flowers Androecium Stamens

Stamens 4, inserted in throat of corolla-tube; anthers 2-celled, opening by longitudinal slits

Morphology Reproductive morphology Flowers Gynoecium Ovary

Ovary superior, with free central ± 4-winged placenta and 4 pendulous ovules; style shortly 2-fid

Morphology Reproductive morphology Fruits

Fruit a capsule opening by 2(–4) thick valves, usually 1-seeded

Morphology Reproductive morphology Seeds

Seed ± viviparous.

Distribution

Genus of eight species according to delimitation, confined to mangroves of both the Old and the New World.

Timothy M. A. Utteridge and Laura V. S. Jennings (2022). Trees of New Guinea. Kew Publishing. Royal Botanic Gardens, Kew

Distribution

A pantropical and subtropical genus of about eight species. In New Guinea four species are recorded.

Morphology General Habit

Shrubs or small trees, up to 30 m tall, roots often with pneumatophores; branches with swollen nodes

Morphology Leaves

Leaves decussate, margin entire, underside often silvery to brownish hairy

Morphology Reproductive morphology Inflorescences

Inflorescences axillary or subterminal, usually umbellate or paniculate, capitate or spicate. Flowers bisexual, actinomorphic, sessile, scented, surrounded by a persistent scale-like bract and 2 bracteoles; calyx 5-lobed, almost free; corolla white turning golden-coloured, actinomorphic or variable zygomorphic, campanulate, 4(–6)-lobed; stamens 4(–6), usually equal, alternate with corolla lobes, inserted in throat or at base of corolla tube; ovary unilocular

Morphology Reproductive morphology Fruits

Fruit an achene

Morphology Reproductive morphology Seeds

Seed 1 by abortion, germinating before the fruit falls.

Ecology

Found growing in saltwater swamps and estuaries at sea level.

Recognition

Species of this genus can be easily recognised being a mangrove tree with opposite, entire leaves with invisible secondary venation on account of the leaves being entirely covered with white silvery hairs below, and the corolla which is initially white, becoming golden. The fruit is usually ovoid and narrowed to an acute apex, and often pale green-grey and viviparous.