Adenodaphne

Adenodaphne is a genus of evergreen trees or shrubs belonging to the family Lauraceae, from New Caledonia. There are five species; they are large trees characteristics of Rainforest in montane laurel forest habitats in New Caledonia and restricted to this region. They belong to an ancient Gondwanian element of Laurales. They have 12 chromosomes.^[1]

Overview

They are leafy canopy trees with erect or spreading branches. It grows to heights of up to 25 metres some species 40 m. and have stout trunks up to 1 metre in diameter. The thick, leathery leaves are dark green. The leaves are glossy laurel type.

The forests are made up of laurel-leaved evergreen hardwood trees, harbouring a rich biota of understorey plants, invertebrates, birds and bats. Adenodaphne require continuously moist soil, and do not tolerate drought.

Trees or shrubs, dioecious. The ecological requirements of the genus, are those of the laurel forest and like most of their counterparts laurifolia in the world, they are vigorous species with a great ability to populate the habitat that is conducive. Adenodaphne genus responde to characteristic formations of laurel forest. The natural habitat is tropical montane laurel forest of New Caledonia which are cloud-covered for much of the year. These species are found in forests that face threats of destruction by human deforestation. It could caused the extinction of the genus across the restricted region area, resulting in the present distribution. They are in danger of extinction due to over exploitation as medicinal plants or timber extraction and also for loss of habitat.

Characteristics

The genus includes species of trees, and shrubs, with evergreen foliage and inconspicuous flowers. Adenodaphne are dioecious and have mostly smooth, glossy, lauroid type leaves. They are evergreen tree with some species growing to 25 m tall.

The inflorescences are consisting in pseudo-umbels (a flat-topped or rounded flower cluster) that are arranged in a racime, sometimes condensed, or a short-shoot or rarely sessile. Each pseudo-umbel with an involucre of decussate, crossed in the form of an X, usually persistent bracts. Leaves glabrous or pubescent, domatia absent.

Inflorescences axillary or solitary seudoumbelas along very short sharp branches, appearing racemose, covered before anthesis by an involucre of bracts decussate.

The flower is from greenish, yellow to white. Male and female flower on different plants. The pollination is done by bees and other insects. The flowers are irregular. The flowers are unisexuals, male flowers with 5 to 20 fertile stamens. The female with a ovary globose and a floral tube. The flowers could be without petals to nine petals by species. The petals when present are equal or unequal, often caducous during anthesis. In the stamens, several inner ones with glands.

Filaments usually longer than the anthers. Anthers are having four locules. The pollen sacs arranged mostly in two pairs above each other, all introrse. Lower pollen sacs are latrorse. The staminodes usually are absent. The tepals usually are deciduous. The Pistillo or gynoecium well developed to absent. Fruits on a light or markedly thickened pedicel, supported by a shallow or deep dome, simple margin. The flower have a flat to deeply cup-shaped receptacle.The fruit is a drupe of variable shape and size.e The most striking are its fruits, The fruit is an ellipsoid to ovoid drupe or berry, and the seed is a single kernel. Plum-like to olive-like drupe settled on a discoid small dome. With shape rounded or ovoid, brown to black, rarely green, purple, reddish, orange to pale yellow. The fruits are a very important food source for birds and other wildlife. The seed dispersion is the result of scattering by columbiform birds mostly but also bats and endemics birds like kagu, parrots or rallidaes. Most seeds pass through the bird's digestive system intact. Seed dispersal via ingestion by vertebrate animals, mostly birds and mammals, is the dispersal mechanism for most tree species.

Species

• Adenodaphne corifolia
• Adenodaphne macrophylla
• Adenodaphne spathulata
• Adenodaphne triplinervia
• Adenodaphne uniflora

References

External links

• Useful New Plants (L. cubeba)