Despite being named for their leaves resemblance to the feathers of the Cassowary Casuarinas are unlikely to attempt to disembowel you should you startle one while out bushwalking, unlikely, but no guarantees.
While they may look like pine trees, Casuarinas (and Allocasuarinas) are flowering plants and belong with the Angiosperms. Within the Casuarinaceae family there are 4 genera and 97 species of which 3 genera and 67 species are found in Australia. The Hunter region has 10* species of Casuarina and Allocasuarina though there are a couple of extra that may just enter into the lower North Coast area.
They are separated into Casuarina and Allocasuarina by the number of teeth on their needles and by the colour of their seeds. The timber has a lovely “oak” grain (hence the common name “sheoak”), burn very hot, wear out saw blades and are an important food source for Black Cockatoos.
For identification purposes a small hand lens is useful, though the zoom function on your phone’s camera will work just as well.
You will need one of the Casuarina “needles” and a cone, grip the needle firmly on both ends and pull apart, the bottom “article” will have a number of small teeth, count the teeth and start from there.
(*and maybe another species if I can get another sample)
1 Leaves (needles) with 6-20 teeth, seed dull, grey or yellow brown (Casuarina) 2
Casuarina cunninghamiana seed
1* Leaves with 4-14 teeth, seed shiny red brown to black (Allocasuarina) 4
Allocasuarina torulosa seed
2 Teeth 12-20, cone 7-10mm diameter. Tree to 20m, frequently suckering, branchlets drooping generally grows in saline conditions.
Casuarina glauca Swamp Oak
2* Teeth 8-12 3
3 Teeth 8-10, cone, barrel shaped, 7-14mm long, 4-6mm diameter. Tree generally to 35m (sometimes 50m+), generally along freshwater creeks and rivers
Casuarina cunninghamiana River Oak
3* Teeth 8-12, cone 13-18mm long (sometimes to 25mm), ball shaped. Tree to 20m, frequently producing suckers, clay soils, uncommon in area.
Casuarina cristata Belah
4 Article ridges with minutely roughened surface 5
4* Article ridges smooth 6
5 Teeth erect, cone 8-14mm dia, 5-12mm length (diameter > length). Tree to 15m, generally on poorer soils, Bulga, Scone, Parkville, Denman to west of Merriwa.
Allocasuarina luehmannii Bulloke
5* Teeth spreading, cone 17-30mm dia, 20-50mm length (length>dia). Tree to 10m, distinctly drooping, on poorer soils, generally in south western part of the Hunter from Bulga and Wybong.
Allocasuarina verticillata Drooping She-oak
6 4 or 5 teeth, cones warty, bark corky, brown. Tree to 15m (often taller), generally in moister, more fertile areas, common on mountains and hills in the upper Hunter.
Allocasuarina torulosa Mountain Oak, Forest Oak
6* not as above 7
7 Cones cylindrical, corky bark (harder, darker than A. torulosa). Tree 5 – 15m, in woodland or tall heath, sandy, poor soils.
Allocasuarina littoralis Black She-oak
7* Cones barrel shaped 8
8 Cone 9-12mm dia, 14-40mm long, top of cone slightly convex. Shrub or tree 2-5m on low open woodland on sandy soils on sandstone ridges, South from Merriwa.
Allocasuarina gymnanthera
8* Top of cone flat to slightly concave 9
9 Cones barrel shaped, 7-12mm dia, 9-20 mm long, top of cone flat or slightly concave. Shrub 1-3m on serpentinite soils, Bralga Tops – Glenrock – Cobark area
Allocasuarina ophiolitica Serpentine She-Oak
9* Cone 5-12mm dia, 5-20mm long, articles often with waxy bloom, Shrub or small tree 1-5m, in heath and low open woodland, on sandstone ridges and hillsides, Goulburn River National Park Allocasuarina diminuta