''Cerbera floribunda'', commonly known as cassowary plum, grey milkwood, or rubber tree, is a plant in the family

Apocynaceae Apocynaceae (from ''Apocynum'', Greek for "dog-away") is a family of flowering plants that includes trees, shrubs, herbs, stem succulents, and vines, commonly known as the dogbane family, because some taxa were used as dog poison Members of the ...

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 Solomon Islands is an island country consisting of six major islands and over 900 smaller islands in Oceania, to the east of Papua New Guinea and north-west of Vanuatu. It has a land area of , and a population of approx. 700,000. Its capita ...

, including north east

Queensland ) , nickname = Sunshine State , image_map = Queensland in Australia.svg , map_caption = Location of Queensland in Australia , subdivision_type = Country , subdivision_name = Australia , established_title = Before federation , established_ ...

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 An inflorescence is a group or cluster of flowers arranged on a stem that is composed of a main branch or a complicated arrangement of branches. Morphologically, it is the modified part of the shoot of seed plants where flowers are formed o ...

is a much branched cyme up to with usually more than 50 flowers. The flowers have 5 white

sepal A sepal () is a part of the flower of angiosperms (flowering plants). Usually green, sepals typically function as protection for the flower in bud, and often as support for the petals when in bloom., p. 106 The term ''sepalum'' was coined b ...

s, a

corolla tube Petals are modified leaves that surround the reproductive parts of flowers. They are often brightly colored or unusually shaped to attract pollinators. All of the petals of a flower are collectively known as the ''corolla''. Petals are usually ...

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 Pedicle or pedicel may refer to: Human anatomy *Pedicle of vertebral arch, the segment between the transverse process and the vertebral body, and is often used as a radiographic marker and entry point in vertebroplasty and kyphoplasty procedures ...

(stem), with a single large seed.

Taxonomy

''Cerbera floribunda'' was first described by

Karl Moritz Schumann Karl Moritz Schumann (17 June 1851 – 22 March 1904) was a German botanist. Schumann was born in Görlitz. He was curator of the Botanisches Museum in Berlin-Dahlem from 1880 until 1894. He also served as the first chairman of the ''Deutsc ...

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 The Maluku Islands (; Indonesian: ''Kepulauan Maluku'') or the Moluccas () are an archipelago in the east of Indonesia. Tectonically they are located on the Halmahera Plate within the Molucca Sea Collision Zone. Geographically they are located eas ...

and

New Guinea New Guinea (; Hiri Motu Hiri Motu, also known as Police Motu, Pidgin Motu, or just Hiri, is a language of Papua New Guinea, which is spoken in surrounding areas of Port Moresby (Capital of Papua New Guinea). It is a simplified version of ...

, and south to

; 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 The white-tailed rat (''Mystromys albicaudatus'') also known as the white-tailed mouse, is the only member of the subfamily Mystromyinae in the family Nesomyidae. This species is sometimes placed in the subfamily Cricetinae due to similarities ...

, 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 Cardiac glycosides are a class of organic compounds that increase the output force of the heart and decrease its rate of contractions by inhibiting the cellular sodium-potassium ATPase pump. Their beneficial medical uses are as treatments for co ...

cerberin Cerberin is a type of cardiac glycoside, a steroidal class found in the seeds of the dicotyledonous angiosperm genus ''Cerbera''; including the suicide tree (''Cerbera odollam'') and the sea mango (''Cerbera manghas''). This class includes digita ...

, 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 The ''Australasian Virtual Herbarium'' (AVH) is an online resource that allows access to plant specimen data held by various Australian and New Zealand herbaria. It is part of the Atlas of Living Australia (ALA), and was formed by the amalgamat ...

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