Казуарина теңізжағалық - екі түршесі бар ағаш

Species of tree
Speciesbox
|image = Casuarina equisetifolia Darwin NT. jpg
|image caption = Subspecies equisetifolia near Darwin
|status = LC
|status system = IUCN3.1
|status ref =
|genus = Casuarina
|species = equisetifolia
|authority = L.
|subdivision ranks = Subspecies
|subdivision =
C. e. subsp. equisetifolia
C. e. subsp. incana
|synonyms ref = ironwood, beach sheoak, beach casuarina or whistling tree is a species of flowering plant in the family Casuarinaceae and is native to Australia, New Guinea, Southeast Asia and India. It is a small to medium sized, monoecious tree with scaly or furrowed bark on older specimens, drooping branchlets, the leaves reduced to scales in whorls of 7 or 8, the fruit long containing winged seeds (samaras) long.

Casuarina equisetifolia is a monoecious tree that typically grows to a height of , sometimes to , and has bark that is smooth and greyish on young specimens, scaly or furrowed on older trees. The branchlets are drooping, up to long, the leaves reduced to scale like teeth about long, arranged in whorls of 7 or 8 around the branchlets. The sections of branchlet between the leaf whorls (the "articles") are long and wide. Male flowers are arranged in spikes long in whorls of 7 to 11.5 per centimetre (per 0.39 in.) the anthers long. The female cones are on a peduncle long and sparsely covered with soft or woolly hairs. Mature cones are long and in diameter, the samaras long. Common names for the tree include Australian pine, horsetair tree, ironwood, beach sheoak; although it has features that seem superficially like a conifer, it is not a pine.

The genus Casuarina was first formally described in 1759 by Carl Linnaeus in Amoenitates Academicae and the first species he described was Casuarina equisetifolia. The specific epithet (equisetifolia) means "horsehair leaved". and in 1982, Lawrie Johnson changed the names to subspecies equisetifolia and incana respectively, in the Journal of the Adelaide Botanic Gardens:
Casuarina equisetifolia L. subsp. equisetifolia, a tree high, the articles long and with 8 to 10 teeth long, the male spikes long, the cones long and wide on a peduncle long. Casuarina equisetifolia subsp. incana (Benth.) L. A. S. Johnson. a tree high, the articles long and with 8 to 10 teeth about long, the male spikes long, the cones long, wide and densely covered with white to rust coloured hairs, on a peduncle long. The epithet incana means "white" or "hoary". There is some doubt as to whether Linnaeus' publication of C. equisetifolia is valid, since he based his description solely on Rumphius's description of Casuarina litorea in Herbarium Amboinense and there are no type specimens.

Casuarina equisetifolia subsp. equisetifolia grows near the sea, behind beaches and near estuaries, sometimes on rocky headlands in Australia, New Guinea, Southeast Asia and India. Casuarina equisetifolia has been introduced to many other continents and islands. It is also regarded as being invasive in South Africa.

Other than ornamental purposes, Casuarina was also explored in for its potential in remediation of textile dye wastewater. Casuarina leaves were found to be useful as absorbent material for the removal of textile dyes such as reactive orange 16 Rhodamine B, methylene blue, malachite green and methyl violet 2b. Similarly the Casuarina dried cone was also reported to be able to remove Rhodamine B, and methyl violet 2b. The Casuarina bark was reported to able to remove methylene blue. Even the Casuarina seed was also found to be useful in dye removal of neutral red and malachite green. The carbon derived from the cones of Casuarina was found to be good absorbent for the landfill leachate, while another laboratory also reported good absorbent for copper ions from aqueous solution.

In Singapore, there is a road named Tanjong Rhu Road because it once had many of these trees growing along the coast from Kallang to Rochor. In the island of Langkawi, Kedah, Malaysia, there is a sand spit in the mouth of the Ayer Hangat river in the Kilim Karst Geoforest Park about 20 km from the town of Kuah also named Tanjung Rhu where these trees line here. The town of Tanjung Aru in Sabah is also named because a lot of this tree (aru) is found in its beach. In the Philippines, the town of Agoo is named after the tree (known as agoho or aroo in the Ilocano language).