Difference between revisions of "Bead tree"

Latest revision as of 15:35, 5 November 2007

Melia azedarach

Melia azedarach in flower

Plant Info

Kingdom:	Plantae
Division:	Magnoliophyta
Class:	Magnoliopsida
Order:	Sapindales
Family:	Meliaceae
Genus:	Melia
Species:	M. azedarach

Binomial name

Melia azedarach
L.

Commonly called Persian Lilac, White Cedar, Cape Lilac, Chinaberry or Bead Tree, Melia azedarach(syn. M. australis, M. japonica, M. sempervivens), is a deciduous tree in the mahogany family Meliaceae, native to India, southern China and Australia. In South Africa it is commonly but erroneously called Syringa, which is in fact the lilac genus. The genus Melia includes four other species, occurring from southeast Asia to northern Australia. They are all deciduous or semi-evergreen small trees.

The adult tree has a rounded to upright top, and measures between 7 and 12 metres in height. The flowers are small and fragrant, with five pale purple or lilac petals, growing in clusters. The fruit is a drupe, marble-sized, light yellow at maturity, hanging on the tree all winter, and gradually becoming almost white.

Timber is of medium density, and ranges in colour from light brown to dark red. In appearance it is readily confused with the unrelated Tectona grandis (Burmese Teak). Melia azedarach in keeping with other members of the family Meliaceae has a timber of high quality, but is under-utilised. Seasoning is relatively simple in that planks dry without cracking or warping and are resistant to fungal infection.

The leaves are up to 50 cm long, alternate, long-petioled, 2 or 3 times compound (odd-pinnate); the leaflets are dark green above and lighter green below, with serrate margins. They have been used as a natural insecticide to keep with stored food, but must not be eaten as they are highly poisonous. A diluted infusion of leaves and trees has been used in the past to induce uterus relaxation.

The flowers are unattractive to bees and butterflies. The hard, spherical seeds were widely used for making rosaries and other products requiring beads, before their replacement by modern plastics.

All parts of the plant are poisonous to humans if eaten. The toxic principles are tetranortriterpene neurotoxins and unidentified resins; it is found most concentrated in the fruits. Some birds are able to eat the fruit, spreading the seeds in their droppings, but 15 grams are a lethal dose for a 22-kilogram pig. The first symptoms of poisoning appear a few hours after ingestion. They may include loss of appetite, vomiting, constipation or diarrhea, bloody faeces, stomach pain, pulmonary congestion, cardiac paralisis, rigidity, lack of coordination and general weakness. Death may take place after about 24 hours.

The plant was introduced around 1830 as an ornamental in the United States (South Carolina and Georgia) and widely planted in southern states. Today it is considered an invasive species as far north as Virginia and Oklahoma.^[1] But nurseries continue to sell the trees, and seeds are also widely available. It has become naturalized to tropical and warm temperate regions of the Americas and is planted in similar climates around the world. Besides the problem of toxicity, its usefulness as a shade tree in urban areas is diminished by its tendency to sprout where unwanted and to turn sidewalks into dangerously slippery surfaces when the fruits fall.