''Cerbera floribunda'', commonly known as cassowary plum, grey milkwood, or rubber tree, is a plant in the family Apocynaceae which is native to the region from

Sulawesi Sulawesi (), also known as Celebes (), is an island in Indonesia. One of the four Greater Sunda Islands, and the world's eleventh-largest island, it is situated east of Borneo, west of the Maluku Islands, and south of Mindanao and the Sulu Ar ...

to the Solomon Islands, including north east Queensland.

Description

''Cerbera floribunda'' is a tree that grows up to in height. The bark is brown to grey/black, and the sap wood and heart wood are both white. Leaves are lanceolate-elliptic, glossy green above and paler beneath, alternate or whorled and crowded towards the ends of the twigs. They measure up to long by wide, with 13 to 20 curved lateral veins and are attached by a long petiole up to long. The inflorescence is a much branched cyme up to with usually more than 50 flowers. The flowers have 5 white sepals, a corolla tube up to by wide with 5 free lobes at the end. They are white with a pink or red centre, are about in diameter, and have a sweet scent. Fruits are a bright blue/purple

drupe In botany, a drupe (or stone fruit) is an indehiscent fruit in which an outer fleshy part (exocarp, or skin, and mesocarp, or flesh) surrounds a single shell (the ''pit'', ''stone'', or '' pyrena'') of hardened endocarp with a seed (''kernel'') ...

measuring about long by wide, slightly pointed and the end away from the pedicel (stem), with a single large seed.

Taxonomy

''Cerbera floribunda'' was first described by Karl Moritz Schumann in ''Die Flora von Kaiser Wilhelms Land'' (K.M.Schumann & U.M.Hollrung, Fl. Kais. Wilh. Land: 111 (1889)) in 1889.

Distribution and habitat

This is a tropical plant and favours abundant water. The native range is from

, east through the Maluku Islands and New Guinea to Solomon Islands, and south to Queensland; it is widespread throughout the range and not considered to be endangered. It is generally found along creeks and marshes and always near permanent water. Altitudinal range in Australia is from sea level to .

Ecology

Fruits are swallowed whole by

cassowaries Cassowaries ( tpi, muruk, id, kasuari) are flightless birds of the genus ''Casuarius'' in the order Casuariiformes. They are classified as ratites (flightless birds without a keel (bird anatomy), keel on their sternum bones) and are native t ...

, who are not affected by the toxins contained within. They then excrete the seeds later, helping to distribute them. The cassowary is the only animal able to provide this function, due to the size of the fruits, and this forms a classic example of a

symbiotic Symbiosis (from Greek , , "living together", from , , "together", and , bíōsis, "living") is any type of a close and long-term biological interaction between two different biological organisms, be it mutualistic, commensalistic, or parasit ...

relationship between the two species. Rodents, in particular the White-tailed rat, eat the kernels after stripping away the flesh but in this case (if they leave some of the kernel behind) it is unlikely to germinate.

Toxicity

As with other species of ''Cerbera'', and indeed many other species in the family Apocynaceae, fruits of this plant are toxic to humans. ''Cerbera'' species contain the cardiac glycoside cerberin, and if eaten will result in nausea, vomiting, abdominal pain, and potentially death. The white sap, which is produced from all parts of the tree, may also cause skin irritation on contact.

Uses

The timber has been used for mouldings and interior finishings in Bouganville and other parts of Papua New Guinea, and for carvings and medicine in the Solomon Islands.

Gallery

File:Gardenology.org-IMG 2637 rbgs11jan.jpg, Inflorescence File:Cassowary-plums.jpg, Fruits File:Cerbera floribunda (8467193315).jpg, Leaves

External links

See
map of recorded sightings
of ''Cerbera floribunda'' at the Australasian Virtual Herbarium

References

{{Taxonbar, from=Q5049514 floribunda Trees of Sulawesi Trees of New Guinea Trees of the Solomon Islands Trees of the Maluku Islands Gentianales of Australia Flora of Queensland