Pultenaea tenebrosa M.A.M.Renner, P.H.Weston & S.Clarke, 2022

Renner, Matthew A. M., Barrett, Russell L., Clarke, Steve, Clugston, James A. R. & Wilson, Peter H. Weston Trevor C., 2022, Morphological and molecular evidence refute a broad circumscription for Pultenaea glabra (Fabaceae: Mirbelieae), with implications for taxonomy, biogeography, and conservation, Australian Systematic Botany 35 (3), pp. 225-277 : 248-250

3. Pultenaea tenebrosa M.A.M.Renner, P.H.Weston & S.Clarke , sp. nov.

Pultenaea sp. Wolgan Cliffs ( S.Clarke 602) NSW Herbarium, PlantNet [https://plantnet.rbgsyd.nsw.gov.au/ accessed 22 Feb. 2022] .

Type: New South Wales, Central Tablelands, Wolgan State Forest, Site 2, ~ 23 km NNW of Lithgow, 8.5 km NE of Cullen Bullen , cliffs on western rim of Wolgan Valley , 9 Nov. 2014, S. Clarke 602 (holo: NSW 883692 ) .

Diagnosis

Distinct in its linear leaves that spread at right angles to the stem, the abaxial leaf surface with bulging cells that bear fine granular ornamentation, the red–brown to black stipules whose lobes are divergent and recurved and completely obscure the branchlets, the calyx with long spreading hairs and coriaceous, pungent, bracteoles that extend as far as, or further than, the adjacent calyx lobe apices.

Spreading multi-stemmed shrub upto 2.0 m tall, peripheral branches nearly horizontal, initiating new branches at base. Branching furcate to fasciculate, irregular. Larger branches and trunk grey–brown with ruminant red–brown traces that become more prominent with branch size. Branchlets yellow–green, almost completely obscured by red–brown recurved stipules. Stipules red–brown aging to dark brown or black, imbricate, furcate, divided for half their length, lobes divergent, sometimes recurved, through as much as 180°; lobe apex acuminate; lamina margins irregularly toothed along their length, the teeth poorly formed but distinct, rounded or acute; stipule lobes eccentrically keeled, the wing on the outside of the keel wider than the inner. Leaves linear to nearly terete, 5.7–16.6 (average 11.1) mm long by 0.4–0.8 (average 0.5) mm wide, spreading at right angles from the stem, dull to mid-green with a hint of yellow below, narrow, inrolled but not completely enclosing the adaxial surface, glabrous; adaxial surface green with a glaucous wash, low pill-box papillae present; abaxial surface discolourous, green laterally (on the surface presented dorsally), red–brown medially (the surface presented ventrally), with a lighter tan–brown central stripe where the midvein is visible; apex tapered to a short point, red–brown; leaf anatomy with ventral epidermal cells hyaline, larger on abaxial surface, subepidermis of orange-pigmented cells present on ventral leaf, three vascular traces present, median trace largest and abutting the orange-pigmented subepidermis; abaxial leaf epidermal cells bulging but not mamillose, bearing granular ornamentation. Inflorescence with flowers closely spaced, but internodes not contracted, with leaves among the flowers progressively decreasing in size at sequential nodes, the shoot continues vegetative growth after flowering; stipules subtending floral leaves similar to sterile stipules, but a little shorter and broader. Flowers sessile. Calyx outer surface with long spreading hairs, the inner surface of each lobe discolourous, margins brown, green below; ventral lobes narrower than the two dorsal lobes, floccose along their median line; the two dorsal lobes floccose along submarginal lines; lobes sometimes bearing scattered hairs on outer surfaces; calyx tube with an indistinct ring of hairs encircling the top of the tube, beneath the sinuses. Bracteoles conspicuous, coriaceous, pungent, weakly keeled, with an indistinct hyaline margin, extending to, or slightly beyond, the level of the calyx lobe apices. Corolla orange–yellow with a faint red flare at the base of standard, keel darker orange–yellow than standard; standard broadly obovate, concave at flower maturity, wings loosely overlaying keel, ligulate above a narrow stipe, almost narrow rectangular with upper and lower margins nearly parallel, apex rounded, base with broad angular auricle; keel asymmetrically elliptic–obovate, upper margin curved, lower margin evenly curved, deepest just beyond mid point towards apex, apex broadly rounded, basal auricle broadly triangular with a rounded apex. Anthers cream, filaments pale orange in dried state. Pollen cream. Ovary and style glabrous ( Fig. 15 , 16 ).

Distribution and ecology

Pultenaea tenebrosa is known from the Wolgan Valley, on the cliff complexes on the western side of the valley, and the pagoda-gully complexes on the Sunnyside Plateau on the south-eastern side. The habitat occupied by P. tenebrosa is challenging to access, and the species may be more widely distributed in suitable situations associated with the Wolgan Valley than current records indicate. The initial site on the eastern side of the Wolgan Valley was a chance discovery, and all subsequent sites were located during targeted searches of pagoda habitats in the area. On the western cliff lines of the Wolgan Valley, Pultenaea tenebrosa occurs almost exclusively on ledges immediately below Mount York claystone. Claystone ledges on the eastern side were also searched with no results, so it seems it occurs on such ledges on the western side of the Wolgan Valley only. The ledges below Mount York claystone on the western cliff-lines bear a sparse canopy of Eucalyptus sp. ( piperita ?), and usually a dense heathy understorey. including Acacia obtusifolia , Allocasuarina sp. , Banksia penicillata , Banksia spinulosa , Dracophyllum secundum , Gahnia filifolia , Leptospermum polygalifolium , Styphelia mutica , Styphelia sieberi , Persoonia myrtilloides , Philotheca obovalis , Epacris reclinata and Xanthorrhoea sp. The soils at these sites are sandy loams or sandy clays.

In three of the populations on the western side of the Wolgan Valley, all plants present pre-fire appear to have been killed outright by the Gospers Mountain fire over the summer of 2019–2020. No basal or epicormic resprouting was seen on any of the charred skeletons of pre-fire adults that could still be identified. However, by June 2020, there had been a large flush of post-fire seedling emergence across the sites, with the largest some 15–20 cm tall at 5 June 2021 ( Fig. 17 ). Two sites had at least 100–200 seedlings each, the third site had a modest 16. So, although the fire has resulted in a many-fold increase in the known number of individuals, it has reduced a significant adult proportion of the species, or perhaps the entire global population, given the entire known extent of the species was burnt, to the current crop of post-fire seedlings. This leaves the species particularly vulnerable in the event of another fire before the current cohort matures and reproduces to replenish the soil seed bank.

Recognition

Pultenaea tenebrosa can be recognised by its combination of linear leaves that spread at right angles to the stem, and the red–brown to black stipules the lobes of which are divergent and recurved and completely obscure the branchlets. Two other distinctive features of P. tenebrosa are the long spreading hairs on the calyx and the coriaceous, pungent, bracteoles that extend as far as, or further than the adjacent calyx lobes. Pultenaea tenebrosa is similar to P. furcata , but the two can be distinguished by the leaf abaxial surface, which in P. tenebrosa bears bulging cells with fine granular ornamentation, whereas in P. furcata the cells each bear a low triangular mamilla. This character may be useful with sterile specimens whose stipules are not, or are suboptimally, recurved.

Conservation status

Pultenaea tenebrosa may qualify for Critically Endangered under the IUCN criteria, given the extent of occurrence is ~ 64 km 2, the species occurs as small, highly fragmented populations, and the populations experience extreme fluctuations in the numbers of mature individuals. During the fires of 2019–2020, fires burnt over the entire range of this species, and killed all mature individuals at three populations on the western side of Wolgan Valley resurveyed in June 2021. Altered fire regimes and browsing by feral herbivores including goats and probably deer constitute the greatest threats to this species.

Etymology

From the Latin tenebrosa , dark, referencing the habit of this species to grow on sheer cliffs of southerly to south-easterly aspect, and the stems densely covered by red–brown to black stipules.

Specimens examined

NEW SOUTH WALES: Central Tablelands: Gardens of Stone National Park : ~ 21 km N of Lithgow , ~ 14 km E of Cullen Bullen , eastern flanks of Sunnyside Ridge in steep gully running into un-named tributary of Carne Creek, 21 Oct. 2015, S. Clarke 703, ( NSW 933334 ); 21 Oct. 2015, S. Clarke 704, ( NSW 933333 ); 21 Oct. 2015, S. Clarke 705, ( NSW 933332 ); 21 Oct. 2015, S. Clarke 706, ( NSW 933331 ); ~ 23 km N of Lithgow , ~ 18 km E of Cullen Bullen , eastern side of ridge above an un-named tributary of Carne Creek, 7 Mar. 2015, S. Clarke 612, ( NSW 933307 ); 17 Mar. 2015, S. Clarke 613, ( NSW 933308 ); ~ 23.5 km N of Lithgow , ~ 18.5 km E of Cullen Bullen , eastern side of ridge above an un-named tributary of Carne Creek , 17 Mar. 2015, S. Clarke 614, ( NSW 933305 ); 17 Mar. 2015, S. Clarke 615, ( NSW 933306 ); ~ 23.5 km N of Lithgow , ~ 18.5 km E of Cullen Bullen , eastern side of ridge in gully running into an un-named tributary of Carne Creek, 21 Oct. 2015, S. Clarke 707, ( NSW 933330 ); 21 Oct. 2015, S. Clarke 708, ( NSW 933329 ); ~ 24 km N of Lithgow , ~ 18 km E of Cullen Bullen , eastern side of ridge above an un-named tributary of Carne Creek, 26 May 2015, S. Clarke 623, ( NSW 933296 ); 26 May 2015, S. Clarke 624, ( NSW 933297 ); ~ 29 km N of Lithgow , ~ 12.5 km NE of Cullen Bullen , southern cliffline of narrow divide between Wolgan and Capertee valleys, 3 June 2015, S. Clarke 625, ( NSW 933293 ); 3 June 2015, S. Clarke 626, ( NSW 933294 ); 3 June 2015, S. Clarke 627, ( NSW 933295 ); Wolgan State Forest : ~ 22 km NNW of Lithgow, 7.5 km NE of Cullen Bullen cliffs on western rim of Wolgan Valley , 9 Nov. 2014, S. Clarke 596, ( NSW 883686 ); 9 Nov. 2014, S. Clarke 597, ( NSW 883687 ); 9 Nov. 2014, S. Clarke 598, ( NSW 883688 ); 9 Nov. 2014, S. Clarke 599, ( NSW 883689 ); 9 Nov. 2014, S. Clarke 600, ( NSW 883690 ); 9 Nov. 2014, S. Clarke 601, ( NSW 883691 ); 9 Nov. 2014, S. Clarke 602, ( NSW 883692 ); ~ 22 km NNW of Lithgow, 7.5 km NE of Cullen Bullen cliffs on western rim of Wolgan Valley , 7 Dec. 2014, S. Clarke 605, ( NSW 883679 ); 7 Dec. 2014, S. Clarke 606, ( NSW 883683 ); 7 Dec. 2014, S. Clarke 607, ( NSW 883684 ); 7 Dec. 2014, S. Clarke 608, ( NSW 883685 ); ~ 24 km N of Lithgow , 10 km NE of Cullen Bullen , cliffs on western rim of Wolgan Valley , 12 Dec. 2014, S. Clarke 609, ( NSW 883674 ); 12 Dec. 2014, S. Clarke 610, ( NSW 883675 ;) ~ 23 km N of Lithgow , ~ 8.5 km NE of Cullen Bullen , cliff lines flanking western side of Wolgan Valley , 27 Sep. 2015, S. Clarke 654, ( NSW 933317 ); 27 Sep. 2015, S. Clarke 655, ( NSW 933318 ); 7 Sep. 2015, S. Clarke 656, ( NSW 933319 ); ~ 23 km NNW of Lithgow, 8.5 km NE of Cullen Bullen cliffs on western rim of Wolgan Valley , 9 Nov. 2014, S. Clarke 603, ( NSW 883693 ); 9 Nov. 2014, S. Clarke 604, ( NSW 883694 ); ~ 25 km N of Lithgow , ~ 8 km NE of Cullen Bullen , ~ 2 km SE of Baalbone Gap, 27 Sep. 2015, S. Clarke 657, ( NSW 933309 ); ~ 24 km N of Lithgow , ~ 10 km NE of Cullen Bullen , cliffs flanking western side of Wolgan Valley , 27 Sep. 2015, S. Clarke 665, ( NSW 934289 ); ~ 24 km N of Lithgow , ~ 10 km NE of Cullen Bullen , cliffs flanking western side of Wolgan Valley , 27 Sep. 2015, S. Clarke 666, ( NSW 934290 ); 27 Sep. 2015, S. Clarke 667, ( NSW 934291 ); ~ 25 km N of Lithgow , ~ 8 km NE of Cullen Bullen , ~ 2 km SE of Baalbone Gap, 27 Sep. 2015, S. Clarke 658, ( NSW 933310 ); 27 Sep. 2015, S. Clarke 659, ( NSW 933311 ;) 27 Sep. 2015, S. Clarke 660, ( NSW 933312 ); 27 Sep. 2015, S. Clarke 661, ( NSW 933313 ); 27 Sep. 2015, S. Clarke 662, ( NSW 933314 ); 27 Sep. 2015, S. Clarke 663, ( NSW 933315 ); 27 Sep. 2015, S. Clarke 664, ( NSW 933316 ); ~ 27.5 km N of Lithgow , ~ 10.5 km NE of Cullen Bullen , ~ 0.5 km S of Mount Jamison , southern cliff line of narrow divide between Wolgan and Capertree valleys, 9 May 2015, S. Clarke 620, ( NSW 933298 ); 9 May 2015, S. Clarke 621, ( NSW 933299 ); 9 May 2015, S. Clarke 622, ( NSW 933300 ); Woolpack Gap , ~ 28.5 km N of Lithgow , ~ 11 km E of Ben Bullen , 19 Aug. 2015, S. Clarke 649, ( NSW 933321 ); 19 Aug. 2015, S. Clarke 650, ( NSW 933320 ); Woolpack Gap , ~ 28.5 km N of Lithgow , ~ 11 km E of Ben Bullen , 19 Aug. 2015, S. Clarke 651, ( NSW 933322 ); 19 Aug. 2015, S. Clarke 652, ( NSW 933323 ); 19 Aug. 2015, S. Clarke 653, ( NSW 933324 ); ~ 13 km N of Lidsdale , ~ 8 km NE of Cullen Bullen , W side of Wolgan Valley , 14 Apr. 2014, S. Clarke s.n., ( NSW 887775 ); Newnes State Forest : ~ 18 km N of Lithgow , ~ 14 km E of Cullen Bullen , pagoda ridge above an un-named tributary of Carne Creek , 30 Apr. 2015, S. Clarke 616, ( NSW 933301 ); 30 Apr. 2015, S. Clarke 617, ( NSW 933302 ); 30 Apr. 2015, S. Clarke 618, ( NSW 933303 ); 30 Apr. 2015, S. Clarke 619, ( NSW 933304 ); ~ 18 km N of Lithgow , ~ 14 km E of Cullen Bullen , pagoda ridge above an un-named tributary of Carne Creek , 21 Oct. 2015, S. Clarke 710, ( NSW 933327 ); 21 Oct. 2015, S. Clarke 711, ( NSW 933326 ); 21 Oct. 2015, S. Clarke 712, ( NSW 933325 ); ~ 22 km N of Lithgow , ~ 18 km E of Cullen Bullen , eastern side of ridge running into an un-named tributary of Carne Creek , 25 Jun. 2015, S. Clarke 641, ( NSW 933292 ); 25 Jun. 2015, S. Clarke 642, ( NSW 933291 ); ~ 22 km N of Lithgow , ~ 18 km E of Cullen Bullen , running into an un-named tributary of Carne Creek , 25 June 2015, S. Clarke 643, ( NSW 933427 ;) 25 June 2015, S. Clarke 644, ( NSW 933428 ); 25 June 2015, S. Clarke 645, ( NSW 933429 ); ~ 22 km N of Lithgow, ~ 18 km E of Cullen Bullen. Near head of gully between pagodas running into an un-named tributary of Carne Creek , 21 Oct. 2015, S. Clarke 698, ( NSW 933339 ); 21 Oct. 2015, S. Clarke 699, ( NSW 933338 ); 21 Oct. 2015, S. Clarke 700, ( NSW 933337 ); 21 Oct. 2015, S. Clarke 701, ( NSW 933336 ); 21 Oct. 2015, S. Clarke 702, ( NSW 933335 ). Ben Bullen State Forest: Cliff-line on western side of Wolgan Valley , E of Bicentennial National Trail , 31 Oct. 2019, M.A.M. Renner 9182 & S. Clarke, ( NSW 1058839 ); 31 Oct. 2019, M.A.M. Renner 9183 & S. Clarke, ( NSW 1058840 ); 31 Oct. 2019, M.A.M. Renner 9184 & S. Clarke, ( NSW 1058841 ); 31 Oct. 2019, M.A.M. Renner 9185 & S. Clarke, ( NSW 1058842 ); 31 Oct. 2019, M.A.M. Renner 9186 & S. Clarke, ( NSW 1058844 ); 31 Oct. 2019, M.A.M. Renner 9187 & S. Clarke, ( NSW 1058845 ) .

Figures

Fig. 15. Pultenaea tenebrosa (= P. sp. Wolgan Cliffs (S. Clarke 602)) line drawing. (a) Flowering branch detail; (b) habit; (c) stipule; (d) flower, lateral view; (e) flower, perianth removed, lateral view; (f) standard petal, ventral view; (g) wing, lateral view; (h) keel, lateral view; (l) leaf abaxial surface; (j) leaf, adaxial surface; (k) leaf cross section and adaxial surface; (l) leaf cross section and abaxial surface. Scale bar: 10 mm (a); 26.7 mm (b); c, 2.7 mm (c); 8 mm (d–h); 5 mm (i, j); 1.6 mm (k, l). All from NSW 1058844, b from dried material, a, c–l from spirit.

Fig. 16. Pultenaea tenebrosa (= P. sp. Wolgan Cliffs (S. Clarke 602)) photos. (a) Shoot apex showing flower in frontal view, note the splayed wings and nearly oblong standard which is taller than it is wide, in contrast to other members of the P. glabra complex; note also the strong glaucous bloom on the adaxial surface of the nearly terete leaves. (b) Close-up of flower buds showing the presence of sparse, long spreading hairs and the long, pungent bracteole, which extend as far as or beyond the calyx lobes; note also the production of normal or nearly normal leaves beneath each flower bud. (c) A flowering shoot, showing the flowers at the shoot apex in a close-set series, in which the internodes are of similar spacing to those separating adjacent vegetative leaves, note the leaves spreading perpendicular to the shoot below the flowers. (d) A group of flowers at the shoot apex, note the long pungent bracteoles, and the glaucous leaf adaxial surface, also note that the wings do not conceal the keel apex, in contrast to P. glabra. (e) Another view of flower buds. (f) Habit. (g) Close-up shoot showing mature stipules, which are characteristically charcoal–black and whose lobes are recurved, note again the leaves spreading perpendicular to the stem axis. All from plants growing in the vicinity of voucher NSW 1058842.

Fig. 17. Pultenaea tenebrosa (= P. sp. Wolgan Cliffs (S. Clarke 602)) seedlings observed on 5 June 2021.