Melaleuca trichostachya Lindl.
Voucher: JAB144
Family: Myrtaceae. Common name(s): Narrow-leaved honey myrtle.
Habit: Tree to 10 m tall. Distribution: Eastern coast of Queensland extending to New South Wales and north-east South Australia.
General features: Density 900-1000 kg/m3. Heartwood red to reddish-brown and darker than sapwood.
Microscopic features:
Vessels Tangential vessel diameter: range 19-88 µm; mean 55 µm; SD 14 µm; average maximum 58-74 µm; n = 122 vessels. Vessels per square millimetre: range 34-36 vessels per mm2; n = 5 sampled areas. Vessels solitary. Perforation plates simple without prominent rim. Heartwood vessels with tyloses. Vessel to vessel pits with vestured pits.
*Fibres/tracheids With numerous, distinctly bordered pits present. Very thin-walled.
Axial parenchyma Information not recorded: axial parenchyma difficult to differentiate from thin-walled fibres on transverse surface using scanning electron microscopy. However, information from endgrain indicates parenchyma are scanty or diffuse to diffuse-in-aggregate.
Rays Rays 1-4 cells wide with uniseriate rays present (n = 55 rays). Rays of uniform width and not wider than vessels. Rays 8-12 per tangential mm (n = 3 sampled areas). Ray height: range 140-420 µm; mean 229 µm; SD 57 µm; n = 31 rays.
Helical thickenings Absent.
Physical and chemical tests: Chrome azurol-s test negative. Heartwood fluorescence present. Froth test weakly positive to positive. Ethanol extract discoloured. Water extract fluorescence absent.
Notes: Absence of tyloses is not diagnostic and their presence is recorded only where they are abundant in heartwood (IAWA 1989: 261).
* At this stage the key makes no distinction between fibres and tracheids as they are difficult to tell apart and there is some confusion in the wood anatomical literature as to their definitions in hardwoods (IAWA: 264). For example, the taxa for which this character was predominantly included - Myrtaceae A (Eucalyptus & Melaleuca) - contain numerous, conspicuous bordered pits that are both called fibre tracheids (Dadswell 1972: 21) and vasicentric tracheids (IAWA: 262).
