taxonID	type	description	language	source
97366C3ECD4047295C5FD224B678F9CD.taxon	description	Previously, morphometric (Palsson et al. 2024, fig. 2 a), and molecular and phytochemical analyses (Sadgrove et al. 2020, fig. 3; Palsson et al. 2024, fig. 2 b, 3 a, 4) supported the recognition of P. cineolifera. The monophyly, distinctive morphological and phytochemical characteristics reported here (Table 1, Fig. 3 – 5) corroborate the status as a distinct species. Putative new species The three putative new species, P. sp. Hawkesbury, P. sp. Olney State Forest and P. sp. Oxley Wild Rivers National Park, that share relatively long, persistent hairy floral prophylls and recurved calyx lobes, clustered as three separate subgroups using morphometric data (Palsson et al. 2024, fig. 2 a). These three entities have sufficient morphological differences (Table 1) to warrant recognition at the rank of species. Recognition of the three entities is corroborated here by phylogenetic analysis (Fig. 3), with the reciprocally monophyletic P. sp. Hawkesbury and P. sp. Olney State Forest form the strongly supported sister clade to the single sample of P. sp. Oxley Wild Rivers National Park. The last is represented in the phylogeny by one of two samples submitted for analysis because only one survived filtering of the DArT seq data. Clearly, further searching in the vicinity of the remote location for additional plants and populations is desirable. Although P. sp. Olney State Forest was represented by multiple samples, these were from the only known location for the species. Other populations in the vicinity and further afield in similar habitats were searched for without success. Narrowly endemic species known from only one population are known in Prostanthera, e. g. P. conniana T. C. Wilson (Wilson et al. 2015), P. gilesii Althofer ex B. J. Conn & T. C. Wilson (Conn and Wilson 2015), P. makinsonii B. J. Conn & T. C. Wilson (Conn and Wilson 2015) and P. volucris R. P. O’Donnell (O’Donnell et al. 2023). We consider that further such species await circumscription, e. g. P. sp. Barren Mountain (L. M. Copeland 2256) NE Herbarium. In Sadgrove et al. (2020, tables 2, 4) the specimen labelled OSF- 3 was a mislabelling for a specimen here determined as P. sp. Hawkesbury. Given this amendment, the essential oil profiles of P. sp. Hawkesbury and P. sp. Olney State Forest differ and corroborate morphological (Table 1) and molecular evidence (Fig. 3) of two new species. In the field, P. sp. Olney State Forest can readily be distinguished from P. sp. Hawkesbury and other members of the study group by a strongly resinous smell on crushing the leaves and young stems. This resinous odour relates to the high levels of 1,8 - cineole together with E - verbenol and menth- 3 - en- 8 - ol (Supplementary Table S 4). There are examples of phytochemistry as a taxonomically informative source of data. In the Lamiaceae, Moshari-Nasirkandi et al. (2024) found that 20 Iranian Salvia L. species each contained a distinct phytochemical profile. Bruňáková et al. (2021) suggested that phytochemical profiling should be included in the integrated plant authentication system for Hypericum L. (Hypericaceae). Both Salvia and Hypericum contain pharmacologically important compounds. Phytochemical analysis is not always useful taxonomically (e. g. Yang et al. 2014; Jiawei et al. 2020) but in our study, despite the small sample sizes, phytochemistry appears to be taxonomically informative given that the results are corroborated by both morphological and DNA data. Despite superficial similarity, P. sp. Oxley Wild Rivers National Park is morphologically and genetically distinct from P. sp. Hawkesbury and P. sp. Olney State Forest. The two known populations of P. sp. Oxley Wild Rivers in the Macleay Gorges subregion of the IBRA NSW North Coast bioregion (Department of Climate Change Energy the Environment and Water 2020) are ~ 12 km apart and separated geographically from both P. sp. Hawkesbury and P. sp. Olney State Forest by over 200 km. The flowering of P. sp. Oxley Wild Rivers National Park occurs later in the season (November) than that of P. sp. Hawkesbury and P. sp. Olney State Forest (September and October respectively).	en	Palsson, Ruth L., Andrew, Rose L., Telford, Ian R. H., Miller, Robert T., Bruhl, Jeremy J. (2025): Towards resolution of the Prostanthera ovalifolia R. Br. assemblage (Lamiaceae: Prostantheroideae): clarification of P. cineolifera R. T. Baker & H. G. Sm. and description of three new species. Australian Systematic Botany 38 (3): 1-25, DOI: 10.1071/SB24003, URL: https://doi.org/10.1071/sb24003
97366C3ECD4147245C48D720B7B7F9D2.taxon	description	(Fig. 4, 5, 6, 7.)	en	Palsson, Ruth L., Andrew, Rose L., Telford, Ian R. H., Miller, Robert T., Bruhl, Jeremy J. (2025): Towards resolution of the Prostanthera ovalifolia R. Br. assemblage (Lamiaceae: Prostantheroideae): clarification of P. cineolifera R. T. Baker & H. G. Sm. and description of three new species. Australian Systematic Botany 38 (3): 1-25, DOI: 10.1071/SB24003, URL: https://doi.org/10.1071/sb24003
97366C3ECD4147245C48D720B7B7F9D2.taxon	materials_examined	Type citation: ‘ Singleton (Howitz). Siberia, Broke, (C. H. Cheesebrough [sic]). Cedar Creek, Millfield (C. F. Laseron) ’. Type: New South Wales. Siberia, Broke, Mar. 1912, C. H. Cheeseborough [sic] s. n. (lecto, here designated: NSW 134514! Residual syn: New South Wales. Singleton, 27 Oct. 1908, Mr Howitz s. n. (BRI AQ 0522596 *); New South Wales. Cedar Creek, Millfield, s. dat., C. F. Laseron s. n. (no specimen located, n. v. )). Shrub, single or multi-stemmed to 1 – 4 (– 6) m tall, 1 – 3 m wide. Branchlets quadrangular, grooved below leaf insertions, covered with scattered glandular trichomes and densely covered with simple non-glandular hairs, each hair usually sinuate (sometimes with a simple curl), mostly ± antrorse, 0.2 – 0.4 mm long, white. Juvenile leaves (including leaves on water shoots) larger than adult leaves, margins often dentate with up to six small teeth per leaf, one known population retains a few dentate teeth on some mature plants. Leaves mid-green above, paler below; petiole 3 – 8 mm long; lamina ovate to lanceolate, 14 – 30 mm long (to 48 mm on juvenile leaves), 5 – 14 mm wide (to 16 mm on juvenile leaves), length to width ratio 2.5 – 4.0, length of maximum width from base to total lamina length ratio 0.3 – 0.6, base attenuate to cuneate, margin entire, apex obtuse, non-glandular hairs absent except for prominent midrib on abaxial surface (there densely distributed, ± antrorse, sinuate, 0.1 – 0.2 mm long), in depressed midrib on adaxial surface (depressed for ~ 2 / 3 length, dense to sparse antrorse non-glandular hairs to 0.25 mm long) and usually proximal third of margin (antrorse simple non-glandular hairs up to 0.25 mm long); abaxial surface moderately to densely glandular (15 – 60 mm − 2), secondary veins often visible; adaxial surface densely glandular (25 – 70 mm − 2), secondary veins indistinct. Inflorescences: thryses to ~ 13 cm long with dichasia usually reduced to single flowers. Floral bracts early caducous, narrowly naviculate, ~ 2.5 mm long, ~ 0.75 mm wide; apex obtuse; abaxially sparsely to densely glandular; adaxially non-glandular hairs mostly absent but margin ciliate with non-glandular hairs to 0.15 mm long. Pedicel 1.25 – 4.75 mm long, moderately covered with non-glandular hairs, antrorse, ~ 0.1 mm long, glandular trichomes moderately common. Floral prophylls caducous, a 1 axis to anthopodium ratio 1.0 – 3.0, opposite or subopposite, narrowly naviculate, 2.2 – 3.0 mm long, ~ 0.1 mm wide, margin entire with curled non-glandular hairs to 0.25 mm long; abaxial surface with scattered to dense glands; glandular trichomes rare on adaxial surface; venation not visible in fresh specimens. Calyx green to maroon, bilobed, both lobes adpressed to the corolla; outer surface with a moderate to dense cover of glandular trichomes, with scattered non-glandular hairs becoming ± glabrescent with age, non-glandular hairs sometimes remaining on abaxial half of calyx tube only; inner surface without non-glandular hairs but non-glandular hairs densely distributed towards margin of lobes, up to 0.2 mm long; margin densely ciliate, with many white non-glandular hairs up to 0.25 mm long; tube 2.0 – 2.5 mm long, sometimes ridged, particularly in dried specimens; abaxial lobe elliptic, 1.0 – 2.0 mm long, 1.5 – 3.0 (– 4.0) mm wide at base; apex usually rounded; adaxial lobe transversely elliptical, 0.5 – 1.0 (– 1.7) mm long, 2.5 – 4.0 (– 6.0) mm wide at base; apex usually rounded, adaxial lobe length to abaxial lobe length ratio 0.3 – 0.8. Corolla pink – mauve; adaxial corolla tube length 3.5 – 6 mm long; outer surface moderately hairy distally (antrorse non-glandular hairs up to 0.2 mm long); margin usually without non-glandular hairs, sometimes scattered minute non-glandular hairs, glandular trichomes occasional; inner surface of tube and lobes with non-glandular hairs or with scattered very short antrorse non-glandular hairs to 0.1 mm, glandular trichomes occasional; abaxial median lobe broadly elliptic to circular, 1.5 – 4 mm long, 1.3 – 3.5 mm wide, 0.8 – 3.25 mm wide below distal lobing, length to width ratio 0.9 – 1.3; apex rounded; margin slightly irregular and slightly undulate, occasionally a shallow sinus up to 0.25 mm deep; lateral lobes very broadly ovate to ovate, 1.5 – 2.75 mm long, 1.0 – 3.25 mm wide, length to width ratio 0.9 – 1.5; apex rounded; margin regular; adaxial median lobe-pair broadly depressed ovate, 0.9 – 2.5 mm long, 1 – 2.5 mm wide, length to width ratio 0.8 – 1.1; margin regular. Stamens inserted 0.7 – 1.6 mm above corolla base; abaxial stamens with filament 1.2 – 2.4 mm long; adaxial stamens with filament 1.2 – 2.0 mm long; anthers cream to pink, locules 0.6 – 0.9 mm long; connective extended to form 1 or 2 basal appendages (one appendage usually shorter than the other), extending beyond base of anther and terminating with 12 – ~ 50 translucent conical hairs; length beyond the anther of appendage including hairs up to ~ 0.25 mm; hairs to 0.1 mm. Pistil 4 – 7 mm long; ovary cylindrical obovoid, 1.1 – 1.3 mm long, diameter at base 0.7 – 0.9 mm, lobes 0.5 – 0.6 mm long; style 3.25 – 5.75 mm long; stigmatic lobes 0.4 – 0.5 mm long. Fruiting calyx only slightly enlarged, adaxial lobe surrounds the folded-over abaxial lobe that conceals developing mericarps. Mericarps maturing to offwhite or cream to charcoal (often mottled), 1.4 – 1.8 mm long, wrinkled and minutely papillose, distally 0.6 – 0.9 mm extended beyond base of style. Phytochemistry The main essential oils in P. cineolifera are 1,8 - cineole, prostantherol and p-cymene. Bicyclogermacrene, caryophyllene oxide and α-pinene are essential oils found in P. cineolifera but not in P. ovalifolia sens. lat. (from Mount Stanley), P. dyarubbin sp. nov. or P. milleri sp. nov. (tables 2, 4 in Sadgrove et al. 2020; Supplementary Table S 4). Aromatic with a scent of 1,8 - cineole when crushed.	en	Palsson, Ruth L., Andrew, Rose L., Telford, Ian R. H., Miller, Robert T., Bruhl, Jeremy J. (2025): Towards resolution of the Prostanthera ovalifolia R. Br. assemblage (Lamiaceae: Prostantheroideae): clarification of P. cineolifera R. T. Baker & H. G. Sm. and description of three new species. Australian Systematic Botany 38 (3): 1-25, DOI: 10.1071/SB24003, URL: https://doi.org/10.1071/sb24003
97366C3ECD4147245C48D720B7B7F9D2.taxon	distribution	Distribution Extant populations of P. cineolifera occur in the Hunter, Kerrabee and Yengo subregions of the Sydney Basin bioregion on the western and southern sides of the Hunter Valley from Wingen Maid north-west of Scone south-east to Bellbird and as far west as Goulburn River National Park. There are historical specimens in New South Wales from Manilla and Upper Moore Creek in the Nandewar bioregion (Fig. 6). Habitat The species grows in skeletal sandy soil at altitudes of up to 630 m on sandstones and conglomerates of the Narrabeen Group (Colquhoun et al. 2022), often associated with ridges, cliff lines and extending down gullies. At the western limit of the range, P. cineolifera is confined to gully bottoms. The vegetation consists of eucalypt open forest or woodland with dominant species Angophora costata, Eucalyptus deanei, E. fibrosa, E. punctata or E. sparsifolia. Phenology Flowers late September to early November; fruiting from mid-November. Conservation status Our extensive fieldwork (J. J. Bruhl, I. R. H. Telford, R. L. Andrew and especially R. L. Palsson) has primarily indicated that of the populations known to us, P. cineolifera is currently protected in Pokolbin State Forest (Bees Nest Ridge and Yellow Rock Road, and parts of Sawpit Road and Broken Back Trail), Singleton Military Area, Wingen Maid Nature Reserve, Wollemi National Park (Cousins Creek), Goulburn River National Park and in the 635 - ha Cedar Creek biodiversity offset, now Cedar Creek Nature Reserve (S. A. J. Bell, unpubl. data, 2017). Only the small population at Wallaby Rocks appears to be threatened. In 2011, Driscoll collected P. cineolifera (NSW 891464) from ‘ top of Wallaby Rocks’. Our two searches have not yielded any plants on top of Wallaby Rocks. Currently, the population is confined to south-western cliff-lines; ‘ pushed’ to cliff lines possibly by fire or grazing pressure. Grazing pressure is likely an important factor, as several heavily browsed plants were found on lower parts of cliff-lines. This possibly threatened population is genetically similar to the larger protected Wingen Maid population (Palsson et al. 2024, fig. 3 b) that unfortunately does have the lowest genetic diversity of the P. cineolifera populations (Palsson et al. 2024, table 4). We recommend that effort be applied to feral goat control at Wallaby Rocks to protect this small, threatened population. Frequent fire is a potential threat to P. cineolifera, as this species is considered fire sensitive (Department of the Environment 2008). The largest known populations are in the Pokolbin area on Bees Nest Ridge and Yellow Rock Road, an area that was severely affected by the 2019 – 20 fires. Fortunately, most populations occurred in areas in which the canopy was unburnt. Six months post fire, there was evidence of large burnt stands of P. cineolifera, some resprouting from trunks and seedling recruitment (Luke Foster, Department of Planning, Industry and Environment, pers. comm., 2021). Prostanthera cineolifera is currently listed as Vulnerable under both Commonwealth and NSW legislation (Office of Environment and Heritage 2019). As of 2018, the number of individuals was <10,000 with Extent of Occurrence (EOO) of 14,000 km 2 and Area of Occupancy (AOO) of 44 km 2 (R. L. Palsson, R. L. Andrew, I. R. H. Telford and J. J. Bruhl, unpubl. data). Since 2018, several more populations of> 1000 individuals and two more locations have been discovered along with recruitment observed by Foster. Also, the Broken Back Range populations were burnt in the summer of 2019 – 20 and 18 months later mass recruitment was observed by R. L. Palsson et al. The status of Vulnerable may still be met for P. cineolifera but discovery of yet more populations in little surveyed areas such as Wollemi National Park would likely enable the status of ‘ Least Concern’ (International Union for Conservation of Nature 2019) to be met for this species. Notes Three geographically separate gatherings are cited in the protologue (Baker and Smith 1912). Only two specimens of these three syntypes could be located; i. e. C. H. Cheeseborough [sic] s. n. (NSW 134514) and Mr Howitz s. n. (BRI AQ 0522596). The NSW specimen was selected as the lectotype as this is a fruiting specimen that was seen by R. T. Baker. The sheet bears the original ‘ Technological Museum, Sydney’ label with R. T. Baker’s name (Fig. 7). By comparison, the syntype of P. cineolifera collected by Howitz is a sterile specimen that does have a ‘ Technological Museum, Sydney’ label but does not bear Baker’s name, [handwriting] and therefore we treat the Howitz sheet as a residual syntype. There is a specimen of P. cineolifera at the Queensland Herbarium (BRI AQ 0336458) that was collected by C. H. Cheesebrough [sic] from the type location that bears two separate annotations in addition to the original label from the Technological Museum, Sydney. One, in red printing has ‘ PART OF TYPE COLLECTION’ and the other a Queensland Herbarium specimen note ‘ syntype Prostanthera cineolifera R. T. Baker & H. B. Sm. J. Proc. Roy. Soc. NSW 46 (1): 105 (1912). ’ However, the date of collection on the original label is ‘ June 1915 ’, 3 years after the publication of the species. Therefore, we consider this material a topotype of no nomenclatural status and not part of the original material for this name. The spelling of the collector of the specimens from Siberia, Broke, is problematic. Both ‘ Cheesebrough’ and ‘ Cheeseborough’ are given on specimen labels and the specimen citation in Baker and Smith (1912). Neither of these spellings appears to have been recorded as a family name in Australia. By contrast, the first mention of the collector’s name in Baker and Smith (1912, p. 104) was ‘ In March of this year a quantity of this plant was forwarded to the Museum, by Mr C. H. Cheesbrough of Siberia, Broke, near Singleton ... ’. So, ‘ Cheesbrough’ appears to be the correct spelling for the collector. Prostanthera cineolifera is distinguished from other species of Prostanthera in the Hunter and Hawkesbury River catchments by a loose open inflorescence, a stem indumentum of sinuate ± antrorse non-glandular hairs and both calyx lobes are firmly adpressed to the corolla in both the developing bud and fully expanded flower. Prostanthera cineolifera has been confused with P. dyarubbin, P. milleri, P. lanceolata and P. ovalifolia. Prostanthera cineolifera can be distinguished from P. lanceolata and P. ovalifolia by the calyx lobes of the latter two species being ± perpendicular to the corolla in both the developing bud and fully expanded corolla. Prostanthera cineolifera can be distinguished from P. dyarubbin and P. milleri that both have more compact inflorescences, persistent hairy floral prophylls and reflexed calyx lobes. In both P. dyarubbin and P. milleri, the ± shield-shaped floral bracts are more often observed, whereas in P. cineolifera, the lanceolate and naviculate floral bracts are only observed on early buds. Vegetative material of P. cineolifera has been confused with P. discolor; both species have similar stem indumenta but the entire leaf margins of P. discolor are ornamented with minute teeth (visible using a hand lens), whereas the proximal third of the leaf margins of P. cineolifera usually have antrorse non-glandular hairs. Selected specimens examined NEW SOUTH WALES: North Western Slopes: Manilla, Oct. 1912, B. J. Moss s. n., (NSW 232116!); Upper Moore Creek, Tamworth, 1933, E. Wyndham s. n. (NSW 134411!); Central Western Slopes: Scone, 31 Aug. 1907, R. H. Cambage s. n. (NSW 227969!); Wingen Maid Nature Reserve, north of Salisbury Trig, 09 Oct. 1997, J. R. Hosking 1498 (CANB, MEL, NE!, NSW); Goulburn River National Park, Morrisons Flat Trail, 11 Oct. 2022, R. L. Palsson 539, J. L. Griffiths, P. Bussell & E. Gill (NE!, NSW!); Wallaby Rocks, Wybong, 8 Sep. 2012, N. J. Sadgrove 291 (CANB, MEL, NE!, NSW); Above Cousins Creek, NW Wollemi National Park, 22 Aug. 1988, S. A. J. Bell s. n. (NSW 424206!). North Coast: Bellbird, Limestone Creek, 7 Oct. 2016, L. M. C. Foster s. n. (NE 106633!); Pokolbin State Forest, Bees Nest Ridge Rd, 10 Oct. 2017, R. L. Palsson 155, R. L. Andrew, J. J. Bruhl & I. R. Telford (NE!); Pokolbin State Forest, Broken Back Trail, 5 Oct. 2017, R. L. Palsson 134 & M. R. Donald, (NE!); Pokolbin State Forest, Yellow Rock Road, 26 Oct. 2021, R. L. Palsson 483, L. M. C. Foster, E. Gill, (NE!, NSW!); Pokolbin State Forest, Sawpit Rd, 1.8 km from junction with Cedar Creek Rd, 6 Oct. 2017, R. L. Palsson 139 & M. R. Donald (NE!, NSW!).	en	Palsson, Ruth L., Andrew, Rose L., Telford, Ian R. H., Miller, Robert T., Bruhl, Jeremy J. (2025): Towards resolution of the Prostanthera ovalifolia R. Br. assemblage (Lamiaceae: Prostantheroideae): clarification of P. cineolifera R. T. Baker & H. G. Sm. and description of three new species. Australian Systematic Botany 38 (3): 1-25, DOI: 10.1071/SB24003, URL: https://doi.org/10.1071/sb24003
97366C3ECD4D47205F0FD708B150F84A.taxon	description	(Fig. 8, 9.)	en	Palsson, Ruth L., Andrew, Rose L., Telford, Ian R. H., Miller, Robert T., Bruhl, Jeremy J. (2025): Towards resolution of the Prostanthera ovalifolia R. Br. assemblage (Lamiaceae: Prostantheroideae): clarification of P. cineolifera R. T. Baker & H. G. Sm. and description of three new species. Australian Systematic Botany 38 (3): 1-25, DOI: 10.1071/SB24003, URL: https://doi.org/10.1071/sb24003
97366C3ECD4D47205F0FD708B150F84A.taxon	materials_examined	Type: New South Wales. Central Coast: Bicentenary Rd, 3.2 km SW of Wisemans Ferry, 1 Sep. 2017, R. L. Palsson 100 & M. R. Donald (holo: NSW!; iso: AD!, BRI!, CANB!, K!, MEL!, MO!, NE 106387!). Prostanthera sp. 10 (Hawkesbury, B. J. Conn 2591), J. D. Briggs & J. H. Leigh, Rare or Threatened Austral. Pl. 81 (1996). Prostanthera sp. Hawkesbury (B. J. Conn 2591) NSW Herbarium, CHAH, Australian Plant Census, https: // id. biodiversity. org. au / tree / 51689388 / 51241805 [accessed 10 Oct 2024].	en	Palsson, Ruth L., Andrew, Rose L., Telford, Ian R. H., Miller, Robert T., Bruhl, Jeremy J. (2025): Towards resolution of the Prostanthera ovalifolia R. Br. assemblage (Lamiaceae: Prostantheroideae): clarification of P. cineolifera R. T. Baker & H. G. Sm. and description of three new species. Australian Systematic Botany 38 (3): 1-25, DOI: 10.1071/SB24003, URL: https://doi.org/10.1071/sb24003
97366C3ECD4D47205F0FD708B150F84A.taxon	description	Prostanthera dyarubbin is characterised by persistent floral prophylls 1.6 – 3.6 mm long, with non-glandular hairs, recurved calyx lobes, a compact inflorescence and no scent of 1,8 - cineole when crushed, and differs from P. cineolifera and P. ovalifolia in the loose open inflorescence, adpressed calyx lobes, caducous floral prophylls and strong 1,8 - cineole scent of these species. Shrub single- to multi-stemmed to (1 –) 4 – 6 m tall, up to 2 m wide. Branchlets quadrangular, distinctly 4 - ridged, covered with scattered glandular trichomes ~ 0.1 mm in diameter and densely covered with antrorse non-glandular hairs in rows on the leaf decurrencies, non-glandular hairs 0.15 – 0.3 mm long, white. Juvenile leaves larger than adult leaves, margins often dentate with up to six small teeth per leaf, some populations retain few to many dentate leaves on mature plants. Leaves dark green above, sometimes tinged with purple, paler below; petiole 2 – 10 mm long; lamina lanceolate, 8 – 30 mm long, 4 – 12 mm wide, length to width ratio 2.0 – 5.0, length of maximum width from base to total lamina length ratio 0.3 – 0.4, base attenuate to cuneate, margin entire, apex obtuse, non-glandular hairs absent except for prominent midrib on abaxial surface (non-glandular hairs distributed densely, ± antrorse, 0.05 – 0.2 mm long) and usually proximal third of margin (antrorse simple non-glandular hairs up to 0.2 mm long); abaxial surface moderately to densely glandular (15 – 30 mm − 2); adaxial surface sparsely glandular (1 – 10 mm − 2), secondary veins indistinct. Inflorescences ± narrow, compact thryses to ~ 6 cm long with dichasia usually reduced to single flowers. Floral bracts caducous, ± obtrullate and concave, vary in shape along axis of inflorescence, central floral bracts 2.5 – 5.0 mm long, 2.0 – 3.5 mm wide; abaxially scattered ± antrorse non-glandular hairs 0.05 – 0.2 mm long, sparsely to densely glandular; adaxially non-glandular hairs absent, occasional glands; margins ciliate with non-glandular hairs to 0.2 mm long. Pedicel 0.5 – 2.7 mm long, scattered non-glandular hairs ~ 0.1 mm long, moderately glandular. Floral prophylls persistent pink to maroon, a 1 axis to anthopodium ratio 3 – 4 (in some populations floral prophylls inserted immediately below calyx), opposite, narrowly elliptic, 1.6 – 3.6 mm long, 0.2 – 0.6 mm wide; margin and abaxial surface moderately to densely covered by non-glandular hairs to 0.3 mm long; adaxial surface with non-glandular trichomes absent, with scattered glands. Calyx usually maroon, bilobed, both lobes recurved; outer surface hairy mainly on the tube (non-glandular hairs to 0.1 mm), densely glandular; inner surface proximally without non-glandular hairs, lobes variable from ± without non-glandular hairs to densely hairy towards margin of lobes; margin sparsely to densely ciliate, with white non-glandular hairs up to 0.1 mm long; tube 1.5 – 2.5 mm long; abaxial lobe broadly ovate, 1.0 – 4.0 mm long, 1.5 – 4.0 mm wide; adaxial lobe broadly depressed ovate, 0.7 – 2.3 mm long, 2.0 – 4.5 mm wide; apex usually rounded; fruiting calyx somewhat enlarged in fruit. Corolla mauve – purple; adaxial corolla tube length 3.5 – 5 mm long; outer surface sparsely to moderately hairy, antrorse non-glandular hairs up to 0.2 mm long, scattered glands; margin usually densely ciliate, non-glandular hairs up to 0.1 mm long; inner surface usually with scattered antrorse non-glandular hairs up to 0.15 mm, particularly on the lobes, scattered glands; abaxial median lobe broadly oblong to ovate, 1.4 – 3.3 mm long, 1.4 – 3.5 mm wide at widest; lateral lobes ovate, 1.7 – 3.3 mm long, 1.2 – 3.5 mm wide, apex rounded to ± acute; adaxial median lobe - pair broadly ovate, each lobe 1.2 – 2.75 mm long, 0.75 – 1.5 mm wide. Stamens with filaments 0.8 – 1.3 mm long; anthers purple to deep purple; locules 0.75 – 1.0 mm long; connective extended to form 1 or 2 basal appendages (one appendage usually shorter than the other), extending beyond base of anther and terminating with 15 – 35 translucent purple conical hairs; length beyond the anther of appendage including hairs 0.1 – 0.3 mm; hairs to 0.1 mm. Pistil 4.5 – 6 mm long; ovary cylindrical obovoid, 0.8 – 1.0 mm long, diameter at base 0.6 – 0.8 mm, lobes 0.4 – 0.5 mm long; style 3.5 – 4.5 mm long; stigmatic lobes to 0.5 mm long. Mericarps maturing to dark brown, ~ 1.5 mm long, wrinkled and minutely papillose, distally ~ 0.8 mm extended beyond base of style. Phytochemistry Although P. dyarubbin contains small quantities of 1,8 - cineole and prostantherol, this species also contains four oils not found in P. ovalifolia sens. lat., P. cineolifera or P. milleri, namely, cadilene, 1 - hexanol, 2 - hexanol and (E) - 2 - hexenal (tables 2, 4 in Sadgrove et al. 2020; Supplementary Table S 4).	en	Palsson, Ruth L., Andrew, Rose L., Telford, Ian R. H., Miller, Robert T., Bruhl, Jeremy J. (2025): Towards resolution of the Prostanthera ovalifolia R. Br. assemblage (Lamiaceae: Prostantheroideae): clarification of P. cineolifera R. T. Baker & H. G. Sm. and description of three new species. Australian Systematic Botany 38 (3): 1-25, DOI: 10.1071/SB24003, URL: https://doi.org/10.1071/sb24003
97366C3ECD4D47205F0FD708B150F84A.taxon	distribution	Distribution Known populations of P. dyarubbin are in the Pittwater and Yengo subregions of the Sydney Basin bioregion, in the environs of the lower Hawkesbury River from Mogo Creek southwards to near Hornsby and from near Webbs Creek eastwards to Ku-ring-gai Chase National Park (Fig. 6). Habitat The species grows on dry ridges, rocky slopes, along cliff lines and in gullies at altitudes up to 150 m on sandstones of the Narrabeen Group and Hawkesbury Sandstone (Colquhoun et al. 2022). The vegetation is eucalypt shrubby open forest with Eucalyptus punctata, Angophora bakeri, A. costata and Corymbia eximia recorded as dominants. Associated species include Allocasuarina littoralis, Astrotricha longifolia, Grevillea buxifolia, G. sericea and Actinotus helianthi. Phenology Flowers are recorded from August – October with fruit from early October. Conservation status The species is conserved in Dharug National Park, Ku-ring-gai Chase National Park, Parr State Conservation Area, Popran National Park, Wisemans Ferry Historic Site and Yengo National Park. There are undoubtedly many more populations of P. dyarubbin that remain undiscovered within the relatively unexplored areas of the distribution. We recommend a status of ‘ Least Concern’ (International Union for Conservation of Nature 2019).	en	Palsson, Ruth L., Andrew, Rose L., Telford, Ian R. H., Miller, Robert T., Bruhl, Jeremy J. (2025): Towards resolution of the Prostanthera ovalifolia R. Br. assemblage (Lamiaceae: Prostantheroideae): clarification of P. cineolifera R. T. Baker & H. G. Sm. and description of three new species. Australian Systematic Botany 38 (3): 1-25, DOI: 10.1071/SB24003, URL: https://doi.org/10.1071/sb24003
97366C3ECD4D47205F0FD708B150F84A.taxon	etymology	Etymology The species epithet is the traditional Dharug (Darug / Daruk) name for the Lower Hawkesbury area. There are several Indigenous spellings for the name of the river (Dyarubbin, Dyarrubin, Deerubbin, Deerubbun). We have selected Dyarubbin, the most commonly used spelling that is also used by the Darug Custodian Aboriginal Corporation (see https: // www. dyarubbin. com /). Notes Prostanthera dyarubbin is morphologically similar to P. milleri Palsson & J. J. Bruhl and P. faucicola Palsson & I. Telford, sharing relatively large persistent hairy floral prophylls, recurved calyx lobes and a compact inflorescence. The known distribution of P. dyarubbin is remote from the known distribution of P. faucicola in the Macleay Gorges (Fig. 6). Prostanthera dyarubbin differs from P. milleri in the lack of the scent of 1,8 - cineole in freshly crushed leaves of the former. The short anther appendages of P. dyarubbin have 15 – 35 conical hairs v. 6 – 12 in P. milleri. The leaves of P. dyarubbin tend to be tougher and narrower that the leaves of P. milleri (length to width ratio 2.0 – 5.0 for P. dyarubbin v. 2.0 – 3.4 in P. milleri). The anthers of P. dyarubbin are purple to deep purple v. mauve for P. milleri. A horticultural selection of the species was brought into cultivation by Henry Parry, Floralands Nursery, Maghoney Creek, New South Wales, under the name Prostanthera ‘ Violet Beauty’. The selection ‘ differs from the typical form in the intensity of the leaf and calyx colouration that is deeper than the normal colour range during flowering’ (Miller 1988). Selected specimens examined NEW SOUTH WALES: Central Coast: Eastern Dyarrubin, 12 June 1996, A. Bofeldt s. n. (NSW 888576!); Wisemans Ferry, ~ 15 km N towards St. Albans, 4 Oct. 1984, T. A. James 568 (NSW!); Wisemans Ferry, 0.1 km S on Old Northern Road, 22 Sep. 1987, B. J. Conn 2591 (NSW!); Kuring-gai Chase, Coal and Candle Creek Road, 12 Oct 1964, O. D. Evans s. n. (NSW 71554!); Bar Point, ~ 3 km along Pacific Motorway from N end of Hawkesbury River bridge, 5 Oct. 2017, R. L. Palsson 133 & M. R. Donald (NE!, NSW!); Hawkesbury River, Oct. 1916, H. M. R. Rupp s. n. (NSW 228302!); Brisbane Water National Park, Mullet Creek, Nov. 1890 L. Stephenson s. n. (NSW 134072!).	en	Palsson, Ruth L., Andrew, Rose L., Telford, Ian R. H., Miller, Robert T., Bruhl, Jeremy J. (2025): Towards resolution of the Prostanthera ovalifolia R. Br. assemblage (Lamiaceae: Prostantheroideae): clarification of P. cineolifera R. T. Baker & H. G. Sm. and description of three new species. Australian Systematic Botany 38 (3): 1-25, DOI: 10.1071/SB24003, URL: https://doi.org/10.1071/sb24003
97366C3ECD49473D5F0FD1E0B238FC43.taxon	description	(Fig. 10, 11.)	en	Palsson, Ruth L., Andrew, Rose L., Telford, Ian R. H., Miller, Robert T., Bruhl, Jeremy J. (2025): Towards resolution of the Prostanthera ovalifolia R. Br. assemblage (Lamiaceae: Prostantheroideae): clarification of P. cineolifera R. T. Baker & H. G. Sm. and description of three new species. Australian Systematic Botany 38 (3): 1-25, DOI: 10.1071/SB24003, URL: https://doi.org/10.1071/sb24003
97366C3ECD49473D5F0FD1E0B238FC43.taxon	materials_examined	Type: New South Wales. Northern Tablelands: Paradise Rocks area, lookout S of trig point, Oxley Wild River National Park, 10 Nov. 2015, M. F. Duretto 4027 & T. L. Collins (holo: NSW 858436 *; iso: CANB!, NE 107073!). Prostranthera faucicola is morphologically similar to P. dyarubbin and P. milleri but differs in the floral prophylls usually being asymmetrical and wider; short anther appendages in P. faucicola with 3 – 6 conical hairs v. 15 – 35 in P. dyarubbin and 6 – 12 in P. milleri (Table 1). Shrub to 2 m tall. Branchlets quadrangular, with scattered glandular trichomes and densely distributed antrorse non-glandular hairs in rows on the leaf decurrencies, non-glandular hairs ~ 0.15 mm long, white. Juvenile leaves not seen, toothed leaves not noted on mature plants. Leaves discolourous, darker above; petiole 2.5 – 8.0 mm long; lamina ovate to lanceolate, 12 – 27 mm long (longer leaves appear to be on a water shoot), 5 – 10 mm wide (wider leaves appear to be on a water shoot), length to width ratio 2.1 – 3.1, length of maximum width from base to total lamina length ratio 0.3 – 0.5, base cuneate, sometimes attenuate, margin entire, apex usually obtuse, mostly without non-glandular hairs except for occasional non-glandular hairs on prominent midrib on abaxial surface, in depressed midrib on adaxial surface (depressed for ~ 2 / 3 length with sparse antrorse non-glandular hairs to 0.15 mm long) and for up to the proximal 2 / 3 of margin (antrorse simple non-glandular hairs up to 0.15 mm long); abaxial surface densely glandular (60 – 100 mm − 2), secondary veins sometimes visible; adaxial surface moderately to densely glandular (25 – 70 mm − 2). Inflorescences compact thryses to ~ 1.5 cm long with dichasia usually reduced to single flowers. Floral bracts caducous, broadly scutiform and concave, apex rounded, vary in shape along axis of inflorescence, central floral bracts 2.75 – 4.0 mm long, 2.75 – 3.25 mm wide, size depends on position in inflorescence and maturity; abaxially scattered non-glandular hairs and scattered to densely glandular, glandular trichomes and non-glandular hairs becoming sparse towards distal margin, non-glandular hairs to 0.15 mm long; adaxially without non-glandular hairs; margin ciliate, non-glandular hairs to 0.05 mm long on distal margin, up to 0.2 mm elsewhere on margin. Pedicel 1.5 – 1.75 mm long. Floral prophylls persistent, opposite, usually inserted at base of calyx, narrowly elliptic, 2.0 – 3.5 mm long, 0.5 – 1.0 mm wide, length to width ratio 3 – 5, not always symmetrical; abaxial surface non-glandular hairy with non-glandular hairs to 0.2 mm long, moderately densely glandular; adaxial surface without non-glandular hairs; margin ciliate to densely ciliate (non-glandular hairs up to 0.25 mm), apex ± without non-glandular hairs. Calyx colour not recorded, bilobed, both lobes recurved, outer surface moderately to densely glandular, scattered non-glandular hairs particularly on the tube, non-glandular hairs up to 0.1 mm long; inner calyx tube and inner abaxial calyx lobe without non-glandular hairs; inner adaxial calyx lobe moderately to densely hairy, non-glandular hairs up to 0.05 mm long; margin ciliate, white non-glandular hairs, 0.02 – 0.05 mm long; tube ~ 1.5 mm long, sometimes ridged in dried specimens; abaxial lobe elliptic, ~ 2.4 mm long, ~ 2.2 – 2.7 mm wide at base, apex rounded; adaxial lobe oblate, ~ 1.2 mm long, 1.9 – 2.5 mm wide at base, apex rounded; adaxial lobe length to abaxial lobe length ratio ~ 0.5. Corolla colour not recorded; adaxial corolla tube length ~ 2.5 mm long; outer surface moderately hairy beyond calyx, ± antrorse non-glandular hairs up to 0.1 mm long, moderately densely glandular on lobes; corolla margin, particularly on adaxial lobes, with white non-glandular hairs 0.02 – 0.05 mm long; inner surface tube and abaxial lobe without non-glandular hairs, adaxial lobe hairy to densely hairy, non-glandular hairs to 0.05 mm long; abaxial median lobe broadly elliptic, 1.6 – 1.9 mm long, 1.2 – 1.8 mm wide, 1.2 – 1.5 mm wide below distal lobing when present, length to width ratio 1.0 – 1.4; apex rounded; lateral lobes usually shallowly triangular to deltate, 1.5 – 2.0 mm long, 1.5 – 2.2 mm wide, length to width ratio 0.8 – 1.3; apex rounded; adaxial median lobe-pair depressed ovate, sometimes distal lobing, ~ 1.0 mm long, 1.2 – 1.8 mm wide, length to width ratio 0.5 – 0.8. Stamens inserted 0.5 – 0.8 mm above corolla base; filaments 0.6 – 1.0 mm long; anther locules ~ 0.75 mm long; anthers, colour not seen; connective extended to form 1 or 2 basal appendages (one appendage usually shorter than the other), extending beyond base of anther and terminating in 3 – 6 translucent conical hairs; length beyond the anther of appendage including hairs ~ 0.4 mm, hairs to 0.05 mm. Pistil ~ 6.0 mm long; ovary cylindrical obovoid, 0.6 – 0.8 mm long, diameter at base 0.5 – 0.6 mm, lobes 0.3 – 0.5 mm long; style ~ 5.0 mm long; stigmatic lobes ~ 0.6 mm long. Fruiting calyx slightly accrescent. Mericarps, mature mericarps not seen.	en	Palsson, Ruth L., Andrew, Rose L., Telford, Ian R. H., Miller, Robert T., Bruhl, Jeremy J. (2025): Towards resolution of the Prostanthera ovalifolia R. Br. assemblage (Lamiaceae: Prostantheroideae): clarification of P. cineolifera R. T. Baker & H. G. Sm. and description of three new species. Australian Systematic Botany 38 (3): 1-25, DOI: 10.1071/SB24003, URL: https://doi.org/10.1071/sb24003
97366C3ECD49473D5F0FD1E0B238FC43.taxon	description	Phytochemistry Has not been assessed.	en	Palsson, Ruth L., Andrew, Rose L., Telford, Ian R. H., Miller, Robert T., Bruhl, Jeremy J. (2025): Towards resolution of the Prostanthera ovalifolia R. Br. assemblage (Lamiaceae: Prostantheroideae): clarification of P. cineolifera R. T. Baker & H. G. Sm. and description of three new species. Australian Systematic Botany 38 (3): 1-25, DOI: 10.1071/SB24003, URL: https://doi.org/10.1071/sb24003
97366C3ECD49473D5F0FD1E0B238FC43.taxon	distribution	Distribution Prostanthera faucicola occurs in the Macleay Gorges subregion of the New South Wales North Coast bioregion where the species is known from two populations in Oxley Wild Rivers National Park, east of Walcha, New South Wales (Fig. 6). Habitat The species grows in shallow skeletal soil on rock outcrops and cliff tops of gorge rims at altitudes of 980 – 1055 m. Vegetation in which the species occurs is recorded as Eucalyptus woodland and heath with Leptospermum variable and Leionema beckleri. Phenology Flowers recorded in November, fruiting mid-November to early December. Conservation status On the basis of three specimens known from two collection sites of unknown population size, we suggest that a ‘ Data Deficient’ status is appropriate under the International Union for Conservation of Nature (2019).	en	Palsson, Ruth L., Andrew, Rose L., Telford, Ian R. H., Miller, Robert T., Bruhl, Jeremy J. (2025): Towards resolution of the Prostanthera ovalifolia R. Br. assemblage (Lamiaceae: Prostantheroideae): clarification of P. cineolifera R. T. Baker & H. G. Sm. and description of three new species. Australian Systematic Botany 38 (3): 1-25, DOI: 10.1071/SB24003, URL: https://doi.org/10.1071/sb24003
97366C3ECD49473D5F0FD1E0B238FC43.taxon	etymology	Etymology The specific epithet is from the Latin fauces (throat or gorge) and - cola (dwelling) referring to the habitat of the species. Notes The informal tag name Prostanthera sp. Oxley Wild Rivers National Park (J. B. Williams s. n. NE 91044) has been used at NE for curatorial purposes and this study. Specimens examined NEW SOUTH WALES: Northern Tablelands: Paradise Rocks, ~ 50 km E of Walcha, 3 Dec. 1978, J. B. Williams s. n. (NE 91044!); Oxley Wild Rivers National Park (2009 addition), on southern side of large rocky outcrop 1.6 km NNW of ‘ Garibaldi’ homestead, 21 Dec. 2008, L. M. Copeland 4355 (NE!).	en	Palsson, Ruth L., Andrew, Rose L., Telford, Ian R. H., Miller, Robert T., Bruhl, Jeremy J. (2025): Towards resolution of the Prostanthera ovalifolia R. Br. assemblage (Lamiaceae: Prostantheroideae): clarification of P. cineolifera R. T. Baker & H. G. Sm. and description of three new species. Australian Systematic Botany 38 (3): 1-25, DOI: 10.1071/SB24003, URL: https://doi.org/10.1071/sb24003
97366C3ECD54473A5C48D287B67FFB9C.taxon	description	(Fig. 12, 13.)	en	Palsson, Ruth L., Andrew, Rose L., Telford, Ian R. H., Miller, Robert T., Bruhl, Jeremy J. (2025): Towards resolution of the Prostanthera ovalifolia R. Br. assemblage (Lamiaceae: Prostantheroideae): clarification of P. cineolifera R. T. Baker & H. G. Sm. and description of three new species. Australian Systematic Botany 38 (3): 1-25, DOI: 10.1071/SB24003, URL: https://doi.org/10.1071/sb24003
97366C3ECD54473A5C48D287B67FFB9C.taxon	materials_examined	Type: New South Wales. Central Coast: Olney State Forest, intersection of Walkers Ridge Rd, ~ 5.1 km from junction with Wollombi Forest Rd, Watagan State Forest, 29 Sep. 1987, B. J. Conn 2613 & B. Timmis (holo: NSW 228852!; iso: CANB, MEL 2523242 *, NE 110202!,? RSA).	en	Palsson, Ruth L., Andrew, Rose L., Telford, Ian R. H., Miller, Robert T., Bruhl, Jeremy J. (2025): Towards resolution of the Prostanthera ovalifolia R. Br. assemblage (Lamiaceae: Prostantheroideae): clarification of P. cineolifera R. T. Baker & H. G. Sm. and description of three new species. Australian Systematic Botany 38 (3): 1-25, DOI: 10.1071/SB24003, URL: https://doi.org/10.1071/sb24003
97366C3ECD54473A5C48D287B67FFB9C.taxon	diagnosis	Diagnosis Prostanthera milleri is morphologically similar to P. dyarubbin and P. faucicola but differs in the strong scent of 1,8 - cineole in freshly crushed leaves in P. milleri, absent in P. dyarubbin and P. faucicola; leaves of P. milleri softer and wider than the leaves of P. dyarubbin (length to width ratio 2.0 – 3.4 in P. milleri v. 2.0 – 5.0 for P. dyarubbin); anthers of P. milleri cream to mauve v. purple to deep purple in P. dyarubbin. Shrub, single to multi-stemmed, 1 – 4 m tall, 1 – 2 m wide, covered with glandular trichomes (~ 0.1 mm in diameter). Branchlets quadrangular, distinctly 4 - ridged, with scattered glandular trichomes and densely distributed antrorse non-glandular hairs in rows on the leaf decurrencies, non-glandular hairs ~ 0.15 mm long, white. Juvenile leaves dentate with up to six small teeth per leaf. Leaves strongly discolourous, mid-green above, paler below; petiole 3 – 15 mm long; lamina ovate to lanceolate, 16 – 47 mm long, 6 – 16 mm wide, length to width ratio 2.0 – 3.4, length of maximum width from base to total lamina length ratio 0.2 – 0.4, base cuneate, sometimes attenuate; margin entire, apex usually obtuse, without non-glandular hairs except for prominent midrib on abaxial surface (sparsely to moderately densely hairy, non-glandular hairs ± antrorse, to 0.15 mm long), in depressed midrib on adaxial surface (depressed for ~ 2 / 3 length and with scattered ± antrorse non-glandular hairs to 0.15 mm long) and usually proximal fifth of margin (antrorse simple non-glandular hairs up to 0.15 mm long); abaxial surface moderately to densely glandular (25 – 45 mm − 2); adaxial surface moderately glandular (10 – 25 mm − 2), secondary veins often visible. Inflorescences ± narrow, ± compact thryses to ~ 1.5 cm long with dichasia usually reduced to single flowers. Floral bracts caducous, scutiform and concave, can vary in shape along axis of inflorescence, central floral bracts 1.7 – 2.6 mm long, 1.7 – 2.3 mm wide; abaxial surface with scattered non-glandular hairs to 0.15 mm long, scattered to densely distributed glands; adaxial surface without non-glandular hairs, occasional glands; margin ciliate, non-glandular hairs to 0.2 mm long. Pedicel 1.5 – 2.25 mm long, scattered non-glandular hairs ~ 0.15 mm long, moderately to densely glandular. Floral prophylls persistent, pale green to pale pink, a 1 axis to anthopodium ratio 2 – 5, opposite, narrowly elliptic, 1.3 – 2.3 mm long, 0.2 – 0.4 mm wide, length to width ratio 4 – 7; abaxially hair- y, scattered glands; margin ciliate to densely ciliate (non-glandular hairs up to 0.2 mm long); adaxially without non-glandular hairs, occasional glands; midrib visible in specimens stored in spirits. Calyx green, green with maroon lobes or all maroon, bilobed, both lobes recurved from corolla; outer surface moderately to densely glandular, scattered non-glandular hairs; margin sparsely to densely ciliate with slightly crisped or adpressed white non-glandular hairs up to 0.1 mm long; inner surface sparsely to densely hairy towards margin of lobes with scattered glandular trichomes, non-glandular hairs up to 0.15 mm long; tube 1.5 – 2.5 mm long, sometimes ridged in dried specimens; abaxial lobe transversely elliptic to oblate, (1.0 –) 1.4 – 2.3 mm long, 1.6 – 3.0 (– 3.8) mm wide at base, apex rounded or occasionally retuse; adaxial lobe transversely elliptic, 0.7 – 1.7 mm long, 2.0 – 3.4 (– 4.1) mm wide at base; apex rounded and margin often shallowly sinuate; adaxial lobe length to abaxial lobe length ratio 0.3 – 1.2. Corolla blue-purple; adaxial corolla tube length 3.0 – 4.5 mm long; outer surface moderately hairy beyond calyx, ± antrorse non-glandular hairs up to 0.1 mm long, sparsely glandular; inner surface tube without non-glandular hairs, sparsely glandular, abaxial lobe usually without non-glandular hairs, adaxial lobe hairy to densely hairy, non-glandular hairs to 0.1 mm long, lateral lobes ± without non-glandular hairs to hairy, non-glandular hairs to 0.1 mm long; corolla margin densely to very densely ciliate with crinkled white non-glandular hairs, 0.04 – 0.15 mm long; abaxial median lobe oblate to elliptic, 1.5 – 3.0 mm long, 1.6 – 3.0 mm wide, 1.0 – 2.2 mm wide below distal lobing, length to width ratio 0.7 – 1.5, apex rounded and margin regular in fresh specimens; lateral lobes usually shallowly triangular to deltate, sometimes oblate, 1.4 – 3.0 mm long, 1.5 – 3.4 mm wide, length to width ratio 0.7 – 1.1, apex rounded, margin regular in fresh specimens; adaxial median lobe-pair depressed ovate, 0.6 – 1.3 mm long, 1.4 – 3.0 mm wide, length to width ratio 0.3 – 0.7, apex rounded, margin regular in fresh specimens. Stamens abaxial stamens inserted 0.6 – 1.5 mm above corolla base, filaments 1.0 – 2.5 (– 4.2) mm long; adaxial stamens inserted 0.5 – 1.1 mm above corolla base; filaments 0.9 – 2.3 mm long; anther locules 0.7 – 1.3 mm long; anthers cream to mauve, connective extended to form 1 or 2 basal appendages (one appendage usually shorter than the other), extending beyond base of anther and terminating with 6 – 12 translucent mauve conical hairs, length beyond the anther of appendage including hairs to ~ 0.2 mm, hairs to 0.1 mm. Pistil 4 – 7.5 mm long; ovary cylindrical obovoid, 0.6 – 0.7 mm long, diameter at base ~ 0.5 mm, lobes ~ 0.3 mm long; style 3.5 – 5 (– 6.8) mm long; stigmatic lobes 0.2 – 0.4 mm long. Fruiting calyx accrescent. Mericarps, mature colour unknown, to ~ 1.8 mm long, wrinkled and minutely papillose. Phytochemistry Although P. milleri contains large quantities of the essential oil 1,8 - cineole and some p-cymene, this species also contains E-verbenol and menth- 3 - en- 8 - ol that are essential oils not found in P. ovalifolia sens. lat., P. cineolifera or P. dyarubbin (tables 2, 4 in Sadgrove et al. 2020; Supplementary Table S 4) and the latter chemical gives the crushed leaves a distinctive sent.	en	Palsson, Ruth L., Andrew, Rose L., Telford, Ian R. H., Miller, Robert T., Bruhl, Jeremy J. (2025): Towards resolution of the Prostanthera ovalifolia R. Br. assemblage (Lamiaceae: Prostantheroideae): clarification of P. cineolifera R. T. Baker & H. G. Sm. and description of three new species. Australian Systematic Botany 38 (3): 1-25, DOI: 10.1071/SB24003, URL: https://doi.org/10.1071/sb24003
97366C3ECD54473A5C48D287B67FFB9C.taxon	distribution	Distribution Prostanthera milleri occurs in Olney State Forest, Watagan Mountains in the Wyong subregion of the Sydney Basin bioregion (Fig. 6). Habitat This species grows on ridges and slopes at altitudes of ~ 450 m. This site is on Hawkesbury Sandstone but downslope of a small basalt remnant (Colquhoun et al. 2022). The vegetation is recorded as eucalypt shrubby open forest – shrubby tall open forest with dominant species Eucalyptus piperita, Corymbia eximia and Syncarpia glomulifera, and an E. agglomerata plantation. Associated species include Allocasuarina torulosa, Acacia elata, Astrotricha latifolia, Zieria smithii, Smilax australis and Calochlaena dubia. Phenology Flowers have been recorded from late September – October with fruit recorded in November. Conservation status There is only one known population of P. milleri, with> 1000 plants recorded in 2017, in an AOO <10 km 2. In 2022, this population had decreased by at least 70 %, likely as a result of the severe drought that ended in early 2020. The population is ± a single age cohort with some recruitment close to the road where the leaf litter is relatively shallow. Downslope where there is leaf litter up to 20 cm deep, no recruitment was noted in 2022. Based on the AOO and severe decline in the number of mature individuals, we suggest a ‘ Critically Endangered’ status is appropriate under the International Union for Conservation of Nature (2019), fulfilling Criteria B 2 (a) and (b) (iv). The known population occurs within a section of state forest marked as ‘ forest management zone 2 - a permanent exclusion to harvesting’ (Mark Drury, Forestry Corporation of NSW, pers. comm., 2022). Nearby ridges in Olney State Forest have been searched unsuccessfully for further populations of P. milleri.	en	Palsson, Ruth L., Andrew, Rose L., Telford, Ian R. H., Miller, Robert T., Bruhl, Jeremy J. (2025): Towards resolution of the Prostanthera ovalifolia R. Br. assemblage (Lamiaceae: Prostantheroideae): clarification of P. cineolifera R. T. Baker & H. G. Sm. and description of three new species. Australian Systematic Botany 38 (3): 1-25, DOI: 10.1071/SB24003, URL: https://doi.org/10.1071/sb24003
97366C3ECD54473A5C48D287B67FFB9C.taxon	etymology	Etymology Honouring Robert T. Miller, who informally documented and provided extensive descriptions for the ‘ Hawkesbury River’ and ‘ Wattagan State Forest’ variants of P. ovalifolia (Miller 1988). Miller was a very active member of the ‘ Prostanthera and Westringia Study Group’ of the Society for Growing Native Plants from the early 1980 s, becoming leader of the study group from 1992 until closure in 2006. Notes The closest known population of P. dyarubbin to the known population of P. milleri is the Mogo Creek population, 25 km to the south-west. We have propagated cuttings of P. milleri and distributed plants to the Australian National Botanic Gardens. Selected specimens examined NEW SOUTH WALES: Central Coast. Olney State Forest, intersection of Walkers Ridge Rd and Murrays Forest Rd, 11 Oct. 2017, R. L. Palsson 166, R. L. Andrew, J. J. Bruhl & I. R. Telford (AD!, BRI!, CANB!, K!, M!, MEL!, MO!, NE!, NSW!, US!); Olney State Forest, intersection of Walkers Ridge Rd and Murrays Forest Rd, 11 Oct. 2017, R. L. Palsson 161, R. L. Andrew, J. J. Bruhl & I. R. Telford (NE!); Olney State Forest, intersection of Walkers Ridge Rd and Murrays Forest Rd, 18 Nov. 2017, R. L. Palsson 215 & M. R. Donald (CANB!, MEL!, NE!, NSW!).	en	Palsson, Ruth L., Andrew, Rose L., Telford, Ian R. H., Miller, Robert T., Bruhl, Jeremy J. (2025): Towards resolution of the Prostanthera ovalifolia R. Br. assemblage (Lamiaceae: Prostantheroideae): clarification of P. cineolifera R. T. Baker & H. G. Sm. and description of three new species. Australian Systematic Botany 38 (3): 1-25, DOI: 10.1071/SB24003, URL: https://doi.org/10.1071/sb24003
97366C3ECD53473A5F6DD5D6B09EF953.taxon	materials_examined	Type: [‘ (T.) v. v. ’]: Australia, Queensland. Port Curtis: ‘ [pencil] Genus Labiatorum [sic] Scutellariae proximum [ink] Shoal Bay Passage III, 26 Aug. 1802, R. Brown s. n. (lecto, here designated: BM 001041052 * JSTOR. Residual syntypes: BM 001041053 * JSTOR, CANB 278989.1!, DAO 411303 * JSTOR, E 00066062 * JSTOR, FI 011221 * JSTOR. MEL 43469 * JSTOR). Notes Mabberley and Moore (2022, p. 555) considered BM 00 1041052 as a ‘ GCFL’ (a good candidate for lectotypification). We agree. This sheet has Brown’s original field tag as cited above (Fig. 14). The location ‘ Shoal Bay’ on ‘ Aug 26 – 1802 ’ fits Mount Westall and the date given in Brown’s diary (Vallance et al. 2001, p. 254). We treat all other syntypes cited above as residual syntypes.	en	Palsson, Ruth L., Andrew, Rose L., Telford, Ian R. H., Miller, Robert T., Bruhl, Jeremy J. (2025): Towards resolution of the Prostanthera ovalifolia R. Br. assemblage (Lamiaceae: Prostantheroideae): clarification of P. cineolifera R. T. Baker & H. G. Sm. and description of three new species. Australian Systematic Botany 38 (3): 1-25, DOI: 10.1071/SB24003, URL: https://doi.org/10.1071/sb24003
