Hibbertia puberula - endangered species listing

The Scientific Committee, established by the Threatened Species Conservation Act, has made a Final Determination to list the shrub Hibbertia puberula Toelken as an ENDANGERED SPECIES in Part 1 of Schedule 1 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. Hibbertia puberula Toelken (family Dilleniaceae) was recently described by Toelken, H.R. (2000) Notes on  Hibbertia (Dilleniaceae) 3 . H. sericea and associated species.  Journal of Adelaide Botanic Garden 19:1-54

2. Hibbertia puberula was previously part of  Hibbertia sericea as described in Harden, G.J. (1990)  Flora of NSW Vol.1 p. 302, UNSW Press, Kensington. The following description of  Hibbertia puberula is taken directly from Toelken (2000): Shrublets with few spreading but ultimately wiry branches up to 30 cm long, sparsely branched, pubescent, often glabrescent.  Vestiture on all parts varying but becoming denser acropetally, consisting of longer over shorter simple hairs and both types usually with pronounced basal tubercles;  on branches and  leaves above and below fine spreading hairs rarely exceeding 0.7 mm;  on outer calyx lobes outside with coarse longer hairs (up to 1.3 mm) antrorsely curved and/or some hooked (but sometimes reclining) over smaller hooked reclining (rarely inclining) ones, inside with fine straight longer and shorter simple hairs over much of the surface;  on inner calyx lobes longer coarse simple hairs usually restricted to along the central vein while short hooked hairs also laterally spreading often almost to the margins.  Leaves with axillary tuft of hairs elongating acropetally to 0.8 mm long, often slightly continued on both sides of decurrent base of petiole; petiole 0.2-0.5 mm long;  lamina oblong-lanceolate to almost linear, (1.2-) 3.2-5.5 (-7.9) x (0.6-) 0.8-1.4 (-1.8) mm, acute, sometimes becoming obtuse, abruptly constricted into petiole, with broad central vein (0.4-0.6 mm wide in the middle) continued into apex but recessed from revolute margins, above and below minutely scabrous to glabrescent, with undersurface not visible.  Flowers single or rarely in a cluster consisting of up to 3 on short shoots subtending the terminal flower, terminal mainly on main branches but also on short shoots; bracts elliptic to elliptic-lanceolate, (2.9-) 3.2-3.5 (-4.0) x 0.6-0.72 mm, leaf-like but often slightly flattened and central vein often indistinct, minutely scabrous to glabrescent.  Calyx more or less accrescent;  outer calyx lobes ovate, more or less beaked with recurved margins towards the apex, (5.8-) 6.8-8.5 (-10.2) x (1.7-) 2.5-3.8 (-4.2) mm, longer than inner ones, outside hispid, one- to two-thirds covered on inside, pubescent to silky;  inner calyx lobes oblong- elliptic to oblong-ovate, (4.9-) 5.8-6.6 (-7.4) x (1.8-) 2.1-2.6 (-3.2) mm, hispid with spreading bristles mainly along the central ridge and becoming abruptly shorter to the sides, which are largely glabrous.  Petals obovate, 6.0-8.3 mm long, broadly bilobed but usually with cuneate base.  Stamens (9) 10-14, subequal; filaments ca. one-third connate; anthers oblong, 1.3-2 mm long, dehiscing by terminal pore and lateral slits.  Pistils 2, almost spherical, with (4-) 6 ovules, style with base recurved along the apex of the ovary, then arched around cluster of anthers, pale.  Fruit puberulous with simple hairs. Seed brown, obovoid, 1.8 x 1.3-1.4 mm, aril a fleshy ring scarcely expanding into surrounding sheath, on lateral base.  Flowering: Oct., Nov.

3. Hibbertia puberula is found in the central coast botanical subdivision in sandy soil often associated with sandstone. Early records are from the Hawkesbury River area and Frenchs Forest in northern Sydney, South Coogee in eastern Sydney, the Hacking River area in southern Sydney, and the Blue Mountains.  Hibbertia puberula has not been collected for over 40 years.

4. Hibbertia puberula is threatened by loss of habitat and the very low number of records for the species suggest that it would be threatened by demographic and environmental stochasticity.

5. In view of the above the Scientific Committee is of the opinion that Hibbertia puberula Toelken is likely to become extinct in nature in New South Wales unless the circumstances and factors threatening its survival or evolutionary development cease to operate.

Associate Professor Paul Adam
Chairperson
Scientific Committee

Proposed Gazettal date: 12/09/03
Exhibition period: 12/09/03 - 24/10/03