Eucalyptus camaldulensis

***Eucalyptus camaldulensis***, also called **river red gum**, is a flowering tree that grows only in Australia. It belongs to the myrtle family. This tree has smooth white or cream-colored bark, long narrow or curved leaves, flower buds grouped in sevens or nines, white flowers, and round fruit with parts that stick out above the edge. It is a well-known tree often found along rivers and streams in inland Australia. It gives shade in very hot places like central Australia.

## Description
The tree usually grows about  tall but can sometimes reach . Its bark is smooth and white or cream with patches of yellow, pink, or brown. Near the bottom, the bark can be rough and loose. Young leaves are long and narrow,  long and  wide. Adult leaves are also long and narrow or curved, dull green or grey-green on both sides, and can be  long and  wide.

The flower buds grow in groups of seven, nine, or sometimes eleven. They are green to creamy yellow and have a pointed cap. The tree flowers mostly in summer, and the flowers are white. The fruit is a hard, round capsule that is 2 to 5 mm long and 4 to 10 mm wide, with parts sticking out above the edge. The flowers bloom for a long time during the year.

Branches or even whole trees can sometimes fall without warning. This makes camping or picnicking near river red gums dangerous, especially if the tree has dead branches or is weak.

## Taxonomy
*Eucalyptus camaldulensis* was first officially described in 1832 by Friedrich Dehnhardt. He wrote about it in a book called "Catalogus Plantarum Horti Camaldulensis".

There are seven accepted subspecies of *Eucalyptus camaldulensis*. They differ mainly in the shape and size of the cap on the flower bud, how the stamens (flower parts) are arranged, and the number of veins in the leaves. The subspecies are: has flower buds with a pointed cap  long, straight stamens, and young leaves that are broad and lance-shaped or egg-shaped.  
* *Eucalyptus camaldulensis* subsp. *arida*: has bluish-green adult leaves with few veins and flower buds with a curved or rounded cap long.  
* *Eucalyptus camaldulensis* subsp. *camaldulensis*: has a strongly pointed cap, stamens that bend inward or irregularly, and narrow lance-shaped young leaves.  
* *Eucalyptus camaldulensis* subsp. *minima*: has small flower buds with a cone-shaped cap  long and broad young leaves usually covered with a powdery layer.  
* *Eucalyptus camaldulensis* subsp. *obtusa*: has white, powdery bark at times and flower buds with a curved, cone-shaped cap  long. 
* *Eucalyptus camaldulensis* subsp. *refulgens*: has very shiny green adult leaves with many veins.  
* *Eucalyptus camaldulensis* subsp. *simulata*:  has a horn-shaped cap  long.

The name "*camaldulensis*" comes from a private garden near the Camaldoli monastery in Naples, Italy, where Dehnhardt worked as the main gardener. This plant grew in the garden for about 100 years before being removed in the 1920s..

Although Dehnhardt was the first to describe *Eucalyptus camaldulensi*s, his book was not well known. In 1847, another scientist named Diederich von Schlechtendal  gave the tree a different name, *Eucalyptus rostrata*, but this name was not valid because it had already been used for another tree. In the 1850s, Ferdinand von Mueller called some river red gum trees *Eucalyptus longirostris*, and in 1856 Friedrich Miquel officially described this name. Finally, in 1934, William Blakely recognized Dehnhardt’s original name, and *Eucalyptus camaldulensis* became the accepted name for the river red gum tree.

Northern Territory Aboriginal names for this species are:
* **aper** (Alyawarr, Anmatyerr), aper or **per** (Eastern Arrernte), **apere** (Kaytetye), **aylpele** (Pintupi Luritja), **itara**, **ngapiri**, **pipalya**, **yitara** (Pitjantjatjara) **apara**, **itara**, **piipalya**, (Waramangu), **kunjumarra** (Warlpiri), **kunjumarra** and **ngapiri** (Western Arrernte).

**Dimilan** is the name of this tree in the Miriwoong language of the Kimberley.

## Distribution and habitat
The dry river beds in central Australia have enough underground water to keep the trees alive. *Eucalyptus camaldulensis *grows in more places naturally than any other eucalyptus tree. It is usually found near rivers and streams, and only a few places have these trees away from water. 

* Subspecies *acuta* is common along rivers from south of Cape York Peninsula in Queensland to the northwest slopes and plains of New South Wales. It is not found near the coast or in dry inland areas.  
* Subspecies *arida* is found in all mainland states except Victoria. It grows in dry areas but only where there is enough moisture under the soil. 
* Subspecies *minima* grows only in South Australia, in the northern Flinders Ranges and northern Eyre Peninsula.

*Eucalyptus camaldulensis* grows in many climates, from tropical to temperate. It usually grows in places with 5 to 20 frosts in winter and very hot summers. Temperatures can range from , with daily changes up to .

## Ecology
, NSW]]
*Eucalyptus camaldulensis*, also called river red gum, grows along rivers and on the flat land near rivers called floodplains. Because it lives near water, it often gets flooded. The tree likes soil that has clay in it. River red gums get water not only from rain but also from regular floods, which help fill the soil with water.. But the Murray–Darling Basin Commission has said snags are important and has suggested stopping their removal from the Murray River.

When river red gums are about 120 to 180 years old, holes start to form in the tree. These tree hollows provide homes for many animals like bats, carpet pythons, and birds. The thick leaves of the tree give shade and shelter from the sun, especially in dry places.

The superb parrot, a bird that is in danger of disappearing, nests in river red gums.

River red gums help other animals by dropping leaves and insects, which provide food and nutrients. This is very important in places where the soil has few nutrients. Even though it is native to some parts of Western Australia, it has spread to other places by escaping from gardens or being planted to help restore land. Because it can survive drought, salty soil, and produces many seeds, it grows easily and quickly. It is called invasive in places like South Africa, California, Jamaica, Spain, and Hawaii, and people work to control its spread there.

## Reproduction and spreading
The flower starts as a small bud with a protective cap called the "operculum". This cap covers the inside of the flower while the male and female parts grow.

The male parts are called stamens. Each stamen has a thin stalk and a top part called the anther, which holds pollen. The anther opens up to release the pollen. During flowering, the stamens grow and surround the flower base.

The female parts are the ovaries, which hold the seeds. The ovaries are separated from the male parts by a disc. A part called the "style" grows from the ovaries up to the flower base, ending in the stigma, which catches pollen.

When the flower blooms, pollen from the anthers can fall on the stigma. Sometimes the flower can pollinate itself, but usually the stigma is ready only after the pollen is released. So, fertilization happens with pollen from other flowers on the same tree or from different trees. Insects, birds, and small animals help move pollen between flowers., while natural flooding happens in winter and spring., and many people recognize it because it grows in many places. People also enjoy using the rivers and floodplains where the river red gum grows for seasonal fun and recreation.

## Population management
The river red gum grows mostly near water, which has helped it survive and spread widely. Because of this, it is not considered endangered. But changes to its home can harm the tree and the animals that live with it. These changes include grazing by animals and controlling water for farming.

Grazing can stop new trees from growing because animals eat or step on young plants. But grazing can also help by clearing thick plants on the ground.  
* Cazneaux Tree, made famous by photographer Harold Cazneaux in his work "Spirit of Endurance".  
* Separation Tree, where people celebrated when Victoria became a separate colony from New South Wales.  
* The Old Gum Tree, where South Australia was officially started.  
* The Queen’s Tree, planted in Kings Park, Perth, Western Australia, in 1954 by Queen Elizabeth II during her first visit to Australia.

## Galleries

File:River Red Gum Bolin Bolin Billabong.JPG|A river red gum near Bolin Bolin Billabong on the Yarra River.
File:Murray River redgums at Echuca.jpg|A view down the Murray River where every tree pictured is a river red gum.
File:700 yr red river gum02.jpg|A 700-year-old tree at the Wonga Wetlands, NSW.
File:Barcoo river, Tambo.JPG|Many river red gums on the banks of the Barcoo River, south-west Queensland.
File:Eucalyptus camaldulensis DSC 5750 (29086898504).jpg|River red gums; the Murrumbidgee River in flood.
File:CSIRO ScienceImage 4682 Casneauxs Tree with the ramparts of Wilpena Pound in the background Flinders Ranges SA 1992.jpg|The Cazneaux Tree, near Wilpena Pound in Flinders Ranges National Park.
File:Eucalyptus camaldulensis - Queen's Tree - Kings Park.jpg|"The Queen's Tree", Kings Park, Perth, WA.
File:RiverRedGum_Hay_NSW.jpg|A river red gum in a bend of the Murrumbidgee River near Hay, NSW.
File:Grampians NP Chatauqua Peak Walk Eucalyptus camaldulensis.jpg|In Grampians National Park, Victoria.

## References