A Casuarina cunninghamiana from Australia

The Casuarina cunninghamiana or the River She-Oak is a large, fast-growing, pine-like tree native to the east of New South Wales and Queensland, Australia. The tree, an evergreen, has thin needle-like, flexible green twigs practically without leaves. An image of a cross section thereof is shown here. The epidermis shows a structure which is a little similar to that of pine needles.

The Casuarina cunninghamiana is one of the tallest trees of its kind and can reach a height of 30-35 m. Its straight stem branches are quite low and its bark is greyish brown, rough and cracked so that it often comes loose in strips. The plants can easily be grown from seeds. In some countries it is considered an invasive species because it can surpass indigenous plant communities.

The wood of this tree is characterized as difficult to dry without warping. It is good firewood and suitable for making charcoal. It is an important stabilizer of banks and soils along waterways. It helps to prevent soil erosion. The structure of the wood is nicely flamed like that of normal oak and is therefore used for carpentry where beauty is important.

The Australian Beefwood as it is also called, prefers a relatively mild climate and tolerates drought if the tree is not too long. It is not a very demanding species with respect to the type of soil and it grows very well in sandy areas with poor soils and close to the sea. In its original environment it can be found along banks of rivers and streams. The tree has been introduced amongst others in Europe because of its beauty and is cultivated in parks and gardens.

In one of the images, crystals present in the plant cells are explicitly made visible by using polarization filters and a lambda plate. 

Note:
The images shown here are made from a prepared slide which belongs to the collection of the Royal Antwerp Society For Micrography, http://www.microscopie.be/. Staining was done with Astra Blue and Safranin.