Leaves: Seedling—deciduous and permanent branches similar in morphology, whorls of 6-8 acute leaf teeth close to the cotyledons, internodes (articles) 0.1-0.4 cm long and branches noticeably ridged. Adult—deciduous and permanent branches noticeably different in morphology, deciduous branches, soft, short (10-25 cm long), shed after 2-3 seasons, thin (about 0.05 cm diameter), leaf teeth in whorls of 8-10 (cunninghamiana) or 6-7 (miodon), yellow at base, darker brown towards apex and marcescent (cunninghamiana) or uniformly yellow, not marcescent (miodon); phyllichnia prominently angular (cunninghamiana) or phyllichnia angular to nearly flat (miodon); internodes (articles) short (0.5-0.8 cm long).

Inflorescences: Male and female on separate trees. Male— grouped in whorls forming short cylindrical spikes 3-4 cm long, at the end of deciduous branchlets. Female—grouped in about 6-7 alternating whorls of 6-8 flowers to eventually form a subglobose cone, about 0.8-1 X 0.8-1 cm, on a stalk about 0.3-0.8 cm long, often among the foliage; cone bracteoles broadly acute (cunninghamiana) or sharpely acute (miodon), bracteoles relatively thin and dehisce rapidly when mature. Flowers Feb.-Mar.

Fruits: Pale brown samaras, ovate, each about 0.2 X 0.1 cm, slightly flattened with a short, barely transparent terminal wing having a prominent middle vein, enclosed by the woody bracteoles of the cone.

Wood: Sapwood is narrow, whitish, not susceptible to Lyctus attack; heartwood is dark reddish or purplish brown, fissile, close-grained except for the medullary rays, moderately strong and very tough when seasoned, comparatively durable for a casuarina, density 710 kg m-3. In the past the timber was used for heads of casks, axe handles, ornamental turnery, shingles and bullock yokes. It is an excellent fuelwood.

Climate: Altitudinal range: near sea level to 1000 m; Hottest/ coldest month: 25-40°C/0-15°C; Frost incidence: low to high (at inland and upland sites); Rainfall: 500-1500 mm per year, uniform to summer max.

Distinctive features: A tall casuarina with soft foliage and small cones that occurs along the banks of permanent freshwater streams.

Casuarina cunninghamiana 1. Bark 2. Fruiting branch 3. Cones before dehiscence 4. Cones after dehiscence 5. Seedling 6. Stand, Murrumbidgee River, near Canberra, A.C.T. 7. Apex of a growing shoot showing recurved leaf teeth (S.E.M.) 8. Male flowers showing anthers (S.E.M.) 9. Leaf teeth at joint (S.E.M.) 10. Female flowers showing the long styles (S.E.M.) 11. Tree, Uriarra Crossing near Canberra, A.C.T.

Coast Sheoak Beach Sheoak, Horsetail Sheoak, Beach Casuarina, Whistling Tree

Casuarina equisetifolia L.

In Australia coast sheoak is usually a small to medium-sized tree 8-16 m tall with a dbh rarely greater than 50 cm. Its form can be very variable ranging from low branching, spreading trees on exposed sites to taller erect trees in more sheltered sites. The crowns have fine branching and pendulous foliage. There are two subspecies, the typical and subsp. incana.

Subsp. equisetifolia extends along coastal north-eastern Australia from Darwin and Tiwi Islands in Northern Territory east to the Cairns region in northern Queensland. It also occurs in Malaysia, Thailand, Myanmar, Vietnam, Melanesia and Polynesia. Subsp. incana is the southern form of this species extending south from Rockhampton in Queensland to Camden Head north of Taree in New South Wales. Populations in the Cooktown to Mackay region represent intergrades between the two subspecies. Subsp. incana also occurs in New Caledonia and Vanuatu.

Coast sheoak occurs along coastal landforms in close proximity to the sea. It is most commonly found along beach foredune systems but it also occurs near estuaries or sometimes on rocky headlands (incana). Soils comprise mainly calcareous sands with sandy loam at depth, derived from tidal and aeolian deposition.

This species usually occurs in pure stands, as few other woody species can tolerate the difficult growing conditions experienced along coastal foreshores.

Related species: Coast sheoak is not considered to have particularly close affinities to other species; phyllichnia have 7-8 leaf teeth per node and its flowers are monoecious.

Publication: Subsp. equisetifolia: Amoen. Acad. 143 (1759). Type: Rumphius, Herbarium Amboinense 3, t. 57. Subsp. incana (Benth.) L.A.S. Johnson: J. AdelaideBot. Gard. 6, 79 (1982). Type: Port Macquarie, New South Wales, May 1819, A. Cunningham 45.

Names: Botanical—Latin equinus (pertaining to horses), Latin folium (a leaf) alluding to the similarity of the cladodes to horse hair, Latin incanus (hoary or white) in reference to the hairy new shoots. Common—alludes to the habitat of the species occurring along coasts, and the conspicuous medullary rays which reminded the early settlers of the same feature in the true oaks (Quercus spp.) of the northern hemisphere.

Bark: Persistent over the whole of the trunk and branches, grey to light grey-brown, smooth on maturing trees, hard, scaly or furrowed on older trees. Young trees have numerous bands of lenticels.

Leaves: Seedling—whorls of 7-8 acute leaf teeth close to the cotyledons, articles (internodes) and branches noticeably ridged. Adult—branchlets pendulous, needle-like, finely longitudinally furrowed, 23-38 X 0.1 cm; phyllichnia prominently angular, glabrous or glaborescent (equisetifolia) or prominently angular to flat (in older growth often on same branchlet), usually densely hairy, particularly when immature (incana), (6-)7-8 leaf teeth per node, 0.3-0.8 mm long; articles (internodes) 0.5-0.7 mm in diameter (equisetifolia) or 0.7-1 mm in diameter (incana).

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