An erect, bushy, aromatic shrub growing to 1
–2 m in height. It has hairy aromatic branches which are elongated and cylindrical, and small (7
–14 mm by 4
–6 mm) leaves which are lance-like with the upper surface covered by hairs. The leaf stalk is very short (approx. 0.5 mm). Leaves dark coloured on the upper surface, whitish underneath, the midrib and lateral veins prominent underneath and impressed above, giving the surface a puckered appearance. Flowers are pale mauve to deep purple, rarely white, 6
–9 mm long, occurring in compact arrangements on the upper end of branches which gives the plant a distinctive appearance.
Plants assigned to Prostanthera stricta from the northern Wollemi area, referred to as Prostanthera aff. stricta, differ from the type form by having leaves which are broad ovate to ovate(length 1–3 times the breadth), and leaf bases which are often broadly rounded. Its leaves may appear triangular when the leaf margins are strongly curved downwards, as in periods of drought or on dried herbarium specimens. The whole plant appears more hairy.
Distribution
Prostanthera stricta occurs from Mt Vincent to Genowlan Mountain in the Capertee Valley. Prostanthera aff. stricta is found at Dingo Creek and the Widden and Baerami Valleys in the Upper Hunter.
Habitat and ecology
- Prostanthera stricta is often a locally dominant undershrub in heath or scrub communities along cliff edges, or as an understorey species within a range of open forest or tall open forest types, or in adjacent transitional communities. Associated vegetation includes Eucalyptus blaxlandii, Eucalyptus cannonii and Eucalyptus viminalis with Acacia implexa and Goodenia ovata. Other associated species recorded at sites include Angophora floribunda, Eucalyptus punctata, Brachychiton populneus, Acacia parvipinnula, Beyeria viscosa, Microlaena stipoides and Cheilanthes species.
Vegetation associated with Prostanthera aff. stricta includes Eucalyptus caleyi, Eucalyptus punctata, Eucalyptus sideroxylon, Eucalyptus tereticornis, Eucalyptus fibrosa, Angophora floribunda, Backhousia myrtifolia, Cryptandra buxifolia, Isopogon dawsonii, Leucopogon muticus, Allocasuarina torulosa, Macrozamia communis, Acacia caesiella and Callistemon salignus.
- Prostanthera stricta flowers from winter to spring. Flowers are likely to be pollinated by insects. In Prostanthera stricta seed dispersal may be assisted by wind in habitat along or close to cliff edges. Prostanthera aff. stricta may be dispersed by water as most known sites are within the riparian zone. Prostanthera aff. stricta is capable of clonal reproduction by layering of branches when growing in the riparian zone.
- Prostanthera stricta grows in areas of both skeletal soil and on deeper, well-drained soil profiles in areas characterised by steep rocky sideslopes, cliff lines, sandstone platforms, or gentle slopes with exposed sandstone outcroppings.. At Mount Vincent the habitat is restricted to the gradation from basalt to sandstone, which is frequently abrupt, occupying a narrow band of 5 to 50 m.
Most known sites of Prostanthera aff. stricta are within the riparian zone.
- Prostanthera stricta is likely to be fire sensitive, with recruitment occurring from the soil seed bank.
- Prostanthera stricta is recorded with abundances of occasional to frequent in populations.
Regional distribution and habitat
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