''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. Notable mem ...

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 List of islands by area, world's 11th-largest island, it is situated east of Borneo, west of the Maluku Islands, and south of Min ...

to the

Solomon Islands Solomon Islands, also known simply as the Solomons,John Prados, ''Islands of Destiny'', Dutton Caliber, 2012, p,20 and passim is an island country consisting of six major islands and over 1000 smaller islands in Melanesia, part of Oceania, t ...

, including northeast

Queensland Queensland ( , commonly abbreviated as Qld) is a States and territories of Australia, state in northeastern Australia, and is the second-largest and third-most populous state in Australia. It is bordered by the Northern Territory, South Austr ...

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 In botany, an inflorescence is a group or cluster of flowers arranged on a plant's Plant stem, stem that is composed of a main branch or a system of branches. An inflorescence is categorized on the basis of the arrangement of flowers on a mai ...

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 Etymology The term ''sepalum'' ...

s, a

corolla tube Petals are modified leaves that form an inner whorl surrounding the reproductive parts of flowers. They are often brightly coloured or unusually shaped to attract pollinators. All of the petals of a flower are collectively known as the ''coroll ...

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 a type of fruit in which an outer fleshy part (exocarp, or skin, and mesocarp, or flesh) surrounds a single shell (the ''pip'' (UK), ''pit'' (US), ''stone'', or ''pyrena'') of hardened endocarp with a seed ...

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 Berlin-Dahlem Botanical Garden and Botanical Museum, Botanisches Museum in Berlin-Dahlem from 1880 until 1894. ...

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 ( ; , ) or the Moluccas ( ; ) are an archipelago in the eastern part of Indonesia. Tectonics, Tectonically they are located on the Halmahera Plate within the Molucca Sea Collision Zone. Geographically they are located in West ...

and

New Guinea New Guinea (; Hiri Motu: ''Niu Gini''; , fossilized , also known as Papua or historically ) is the List of islands by area, world's second-largest island, with an area of . Located in Melanesia in the southwestern Pacific Ocean, the island is ...

, 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

southern cassowaries The southern cassowary (''Casuarius casuarius''), also known as double-wattled cassowary, Australian cassowary, or two-wattled cassowary, is a large flightless black bird, found in Indonesia, Papua New Guinea, and northeastern Australia. It is ...

, 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 (Ancient Greek : living with, companionship < : together; and ''bíōsis'': living) is any type of a close and long-term biolo ...

relationship between the two species. Rodents, in particular the

giant white-tailed rat The giant white-tailed rat (''Uromys caudimaculatus'') is an Australian rodent native to tropical rainforest of north Queensland, with subspecies occurring in New Guinea and the Aru Islands. It is one of the largest rodents in Australia, reaching ...

, 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 include treatments for ...

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:Cerebra floribunda.jpg, Flower File:Cassowary-plums.jpg, Fruit File:Cerbera floribunda (8467193315).jpg, Foliage and flowers

References

External links

View a map
of historical sightings of this species 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 amalgama ...

View observations
of this species on

iNaturalist iNaturalist is an American 501(c)(3) nonprofit social network of naturalists, citizen scientists, and biologists built on the concept of mapping and sharing observations of biodiversity across the globe. iNaturalist may be accessed via its web ...

View images
of this species on Flickriver.com {{Taxonbar, from=Q5049514 floribunda Taxa named by Karl Moritz Schumann Plants described in 1889 Trees of Sulawesi Trees of the Maluku Islands Trees of Papuasia Flora of Queensland Gentianales of Australia