Prostanthera staurophylla F. Muell. sensu stricto - endangered species listing

The Scientific Committee, established by the Threatened Species Conservation Act, has made a Final Determination to list the shrub Prostanthera staurophylla F. Muell. sensu stricto as an ENDANGERED SPECIES in Part 1 of Schedule 1 of the Act, and as a consequence, to omit reference to Prostanthera staurophylla F. Muell. from Part 1 of Schedule 2 (Vulnerable species) of the Act. Listing of endangered species is provided for by Part 2 of the Act.

NSW Scientific Committee - final determination

The Scientific Committee has found that:

1. Prostanthera staurophylla F. Muell.  sensu stricto (family Lamiaceae) is described by Hunter  et al. (in press) as an "erect to spreading shrub 1-1.8 m high. Branches ± terete to sub-quadrangular, densely glandular-pubescent with sub-sessile glands, tubercular hairs throughout, non-glandular hairs multicellular, curled or crisped, 0.5-1.2 mm long, white. Leaves lime- to dark green, strongly aromatic (when crushed); petiole distinct, 0.6-1.2 mm long; lamina elliptic to oblong or more commonly widely trullate or cross-shaped, deeply (1-) 3 (-7)-lobed, 2-9 mm long, 0.9-7 mm wide, discolorous, abaxial surface paler and densely covered with curled or crisped non-glandular hairs, particularly along mid-vein and lateral veins towards lobes where distinct and raised, margin recurved but never revolute; adaxial surface sparsely glandular when young, less dense towards petiole, sparsely scabrous particularly on margins and apices, mid-vein depressed. Flowers axillary, solitary. Podium 0.7-1.5 mm long, sparsely hairy and glandular. Prophylls persistent, inserted below the calyx base [propodium to anthopodium ratio 3-4], elliptic to narrowly ovate, 0.3-0.4 mm long, 0.15-0.25 mm wide, glandular. Calyx lime-green, sometimes with a purple-maroon tinge; outer surface sparsely glandular; inner surface glabrous; margin fimbriate with multicellular white hairs 0.2-0.3 mm long; abaxial lobe broadly ovate, 1.5-2.5 mm long, 2-2.5 mm wide, apex rounded; adaxial lobe broadly ovate, 1.2-1.6 mm long, apex obtuse to rounded. Corolla 15-18 mm long, bluish mauve with darker markings; outer surface glabrous; inner surface sparsely hairy; tube 8-10 mm long; abaxial median lobes transversely broad-spathulate, 5-6 mm long, 6-7 mm wide, apex irregular, rounded and bilobed; lateral lobes elliptic, 3-4 mm long, 3-4 mm wide, apex rounded; adaxial median lobe-pair very depressed ovate, 1-2 mm long, 9-10 mm wide. Stamens inserted 3-5 mm above base of corolla; filaments 3-6 mm long; anthers 0.8-1.4 mm long, connective extended to form a basal appendage 1-1.4 mm long, terminating in narrowly triangular trichomes. Pistil 7.5-9 mm long."

2. Prostanthera staurophylla sensu stricto, as described above, was previously considered to be synonymous with  P. teretifolia, with the two taxa combined under the name  P. staurophylla in the  Flora of NSW (Harden 1992). Following the rediscovery of a population that matches the Type material of  P. staurophylla ( sensu stricto) , the two distinct taxa are now recognised as separate species (Hunter  et al. in press). This Determination therefore does not apply to the broader (previously recognised) taxon described by Harden (1992), referred to here as  P. staurophylla sensu lato. All other records of  P. staurophylla sensu lato are now referred to as  P. teretifolia, leaving  P. staurophylla sensu stricto currently restricted to a single location.

3. P. staurophylla sensu stricto is currently known from a single granite outcrop in the Tenterfield area, in the New England Tableland Bioregion (Thackway & Creswell 1995). The geographic distribution of the species is therefore very highly restricted. Within its only known population,  P. staurophylla sensu stricto occurs in shallow skeletal soil in rock crevices (Hunter  et al. in press).

4. The total population of P. staurophylla sensu stricto is currently estimated to contain fewer than 500 individuals, of which few are mature (J. T. Hunter, pers. comm.). The number of mature individuals is therefore very low.

5. The only known population of P. staurophylla sensu stricto occurs in a nature reserve. However, the species is threatened by environmental and demographic stochasticity due to the small size, and very highly restricted distribution.

6. The Scientific Committee is of the opinion that P. staurophylla sensu stricto is not eligible to be listed as a Critically Endangered Species.

7. Prostanthera staurophylla F. Muell.  sensu stricto is eligible to be listed as an endangered species as, in the opinion of the Scientific Committee, it is facing a very high risk of extinction in New South Wales in the near future as determined in accordance with the following criteria as prescribed by the Threatened Species Conservation Amendment (Listing Criteria) Regulation 2005:

Clause 17

The total number of mature individuals of the species is observed, estimated or inferred to be:

(b) very low.

Associate Professor Lesley Hughes
Chairperson
Scientific Committee

Proposed Gazettal date: 13/04/06
Exhibition period: 13/04/06 - 09/06/06

References :

Harden GJ (1992) Flora of New South Wales. Volume 3. (University of New South Wales Press: Kensington.)

Hunter JT Williams JB & Conn BJ (in press) Rediscovery of Prostanthera staurophylla F. Muell. and reinstatement of  P. teretifolia Maiden & Betche (Lamiaceae).  Telopea.

Thackway R, Creswell ID (1995) An interim biogeographic regionalisation for Australia: a framework for setting priorities in the National Reserves System Cooperative Program. Version 4.0. ANCA, Canberra.