Tetratheca shiressii

Small shrub to about 0.7 metres tall, often multi-stemmed with a radial spread to about 0.3 metres.

It is endemic to NSW, growing mainly in two disjunct patches on the central coast subdivision; between Wollongong and Sydney; and then from around Berowra – north through the Gosford area, to Watagan State Forest with some outlying records further west on Putty Road at Howes Valley. Interestingly, it is absent between Berowra and Botany Bay. 

It is generally found in heathland on rocky or sandy sites, as well as swamp-heath or wet heath. 

In Tetratheca spp., leaves are simple and can be arranged alternately or in opposite pairs or whorls. Some species can exhibit varying leaf arrangements (dimorphic). In this species, leaves are in opposite pairs or in whorls of 3 or 4 to 5, to 20 mm long and 1 mm wide, linear, with revolute margins. A second description is given for leaves on hairy (assume younger) branchlets: in whorls of 3 to 5, occasionally opposite, broad-elliptic to ovate or subcircular, to 12 mm long and 6 mm wide, with flat to revolute margins. 

Tetratheca spp. tend to produce solitary or paired flowers in leaf axils, well beyond the foliage. They typically have 4 petals which resemble an even cross (some flowers can have 5 petals), with 8 stamens and 1 carpel. Flowers often point downwards (pendent) which attracts certain insects. In this species, flowers are solitary or paired, deep lilac-pink, to about 20 mm across, occurring mostly in July to October.

Tetratheca spp. produce fruit as capsules which open longitudinally. In this species, the capsules are to 5 mm long and opening longitudinally; seeds about 3 mm long.