Pultenaea furcata M.A.M.Renner & R.L.Barrett, 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 : 245-246

2. Pultenaea furcata M.A.M.Renner & R.L.Barrett , sp. nov.

Pultenaea sp. Dingo Creek ( M. A. M.Renner 9176 & J. M.Cohen) NSW Herbarium, PlantNet [https://plantnet.rbgsyd.nsw.gov.au/, accessed 22 Feb. 2022] .

Type: New South Wales, Central Tablelands, Newnes State Forest, track to Dingo Creek south of Deep Pass Trail , 27 Sep. 2019, M. A. M. Renner 9181 & J . Cohen (holo: NSW 1058825 ; iso: CANB, MEL) .

Diagnosis

Distinct in the glabrous, linear leaves, with abaxial surface cells each bearing a low triangular mamilla, the glabrous branchlets, the inflorescence terminating leafy shoots, and villous calyx.

Spreading multi-stemmed shrub up to 2.5 m tall, openly branched, bark red–brown to grey–brown, slightly fissured at base. Branchlets yellow–green, glabrous. Stipules red–brown aging to dark brown, divided to just over halfway, lobes diverging, keeled to close to the apex, keels in each lobe eccentric, prominent and convergent at the top of lamina, then running parallel down either side of the leaf insertion; disc flaring slightly towards base but not by much; overall, the disc is quite rectangular; margins irregularly and sparsely toothed. Leaves glaucous above, dull mid-green below; linear to narrow oblanceolate, 7.3–18.7 (average 12.0) mm long by 0.4–1.0 (average 0.7) mm wide, margins upturned to inrolled, when dry obscuring the adaxial surface, glabrous, but a couple of hairs are present on either side of the pulvinus; apex mucronate, orange–brown; abaxial surface with low triangular mamillae formed by single epidermal cells; adaxial surface glaucous, bearing numerous pill-box cuticular papillae; three vascular traces present, medial largest; adaxial epidermis hyaline or slightly tan-pigmented, no orange-pigmented cells are present. Inflorescence terminal on shoot that ceases growth; leafy throughout, although leaf length decreases from the base to the apex of the inflorescence; internodes contracted; within the inflorescence leaves reduced to a red–brown, hair-bearing spine fused with the stipule, between the two stipule keels, and not extending as far as the apex of the stipule lamina. Flowers in clusters of 7–12, shortly pedicellate to nearly sessile, pedicel villous; long red–brown trichomes in the flower axil adjacent the pedicel. Calyx green with wine-red margins; copiously ciliate in bud, hairs evenly distributed and retained through to fruit; densely villous throughout including tube and lobes, hairs tending to be longer at the apex of the tube; lobes long, narrow, acuminate and pungent-tipped; lobe margins floccose or ciliolate with dense short curled hairs; lobe apices obtuse with an acuminus; inner surface of lobes with a hyaline margin subtended by a dark brown to black band, medial part green; dorsal calyx lobes conspicuously reflexed. Bracteoles bronze–brown, villous hairy to near their apex, apex mucronate; papillae present on their uppermost margins. Corolla orange–yellow, with faint red semicircular marking at base of standard, otherwise lacking red markings, keel paler than rest of the flower; greenish-cream to pale yellow; standard rotund above a basal stipe, folded not flat at flower maturity, apex emarginate; wings laterally splayed, ligulate to slightly rectangular–obovate above a long basal stipe, upper and lower margins straight, slightly divergent towards rounded apex, basal auricle a broad rounded triangle. Keel asymmetrically elliptic, upper margin linear, lower margin evenly curved, broadest at mid-point, apex broadly rounded, basal auricle triangular with the auricle apex rounded. Anthers and pollen cream. Ovary glabrous, style with a few sparse sharp, stiff, hairs on the lower surface. Pods not seen ( Fig. 13 , 14 ).

Distribution and ecology

Pultenaea furcata is known from the upper Dingo Creek catchment, on the eastern side of the Newnes Plateau. Three populations are known, each occurring in slightly different ecological settings. In the upper catchment, Pultenaea furcata grows in deep humic soils within small, steep, south-western facing gullies between sandstone pagodas and outcrops of the Narrabeen Group. Here, it grows within a mixed shrubland with Dillwynia sp. , Epacris browniae Colby , Prostanthera sp. and other shrubs. Alongside a tributary of Dingo Creek, P. furcata grows as a dominant component of riparian shrub layer within a shallow gully with a northerly aspect, and beneath a discontinuous Eucalyptus canopy, with Leptospermum sp. At the third known population P. furcata grows on an alluvial terrace beneath a mixed canopy of Leptospermum sp. and Eucalyptus sp. in a sharp gully punctuated by sandstone pagodas.

Recognition

Pultenaea furcata is similar to P. glabra in branching architecture, wherein inflorescences terminate leafy shoots, and vegetative growth is continued by branching immediately below the inflorescence, with the result that branching pattern is furcate to whorled. Pultenaea furcata differs from P. glabra in the linear leaves up to 1.0 mm wide (oblanceolate and up to 2.1 mm wide in P. glabra ), the abaxial surface cells each bearing a low triangular mamilla (only bulging and with fine granular ornamentation in P. glabra ), and the calyx is villous (glabrous in P. glabra ).

Conservation status

Pultenaea furcata may qualify for listing as Critically Endangered, given the small known area of occupancy and extent of occurrence, currently estimated to be less than 5 km 2, and extreme fluctuations in the numbers of adult individuals. At the type locality, all but two of the adult plants observed in September 2019 were killed by the fires of October 2019 – January 2020. Search and survey work should be undertaken ahead of any listing proposal to establish the likely limits of the distribution of P. furcata , which may include more remote sites along the eastern edge of Newnes Plateau. This species was unknown before this study commenced, suggesting its distribution may well be restricted to the Dingo Creek catchment and relatively inaccessible and remote country to the north thereof.

Etymology

From the Latin furcata , forked, in reference to the bifurcating to whorled branching architecture, which is a function of the terminal determinate inflorescence, and is a distinctive feature shared with only P. glabra within the complex.

Specimens examined

NEW SOUTH WALES: Central Tablelands: Newnes State Forest: Tributary of Dingo Creek at crossing with firetrail, NE side of Newnes Plateau , 27 Sep. 2019, M. A. M. Renner 9170 & J. M. Cohen , ( NSW 1058826); ibid, 27 Sep. 2019, M. A. M. Renner 9171 & J. M. Cohen, ( NSW 1058827 ); 27 Sep. 2019, M. A. M. Renner 9172 & J. M. Cohen, NSW1058828 ; M. A. M. Renner 9173 & J. M. Cohen, 27 Sep. 2019, ( NSW 1058829 ); 27 Sep. 2019, M. A. M. Renner 9174 & J. M. Cohen, ( NSW 1058830 ); 27 Sep. 2019, M. A. M. Renner 9175 & J. M. Cohen , ( NSW 1058832 ); track to Dingo Creek south of Deep Pass Trail, 27 Sep. 2019 , M. A. M. Renner 9176 & J. M. Cohen, ( NSW 1058819 ); ibid, 27 Sep. 2019 , M. A. M. Renner 9177 & J. M. Cohen, ( NSW 1058821 ); 27 Sep. 2019 , M. A. M. Renner 9178 & J. M. Cohen, ( NSW 1058822 ); 27 Sep. 2019 , M. A. M. Renner 9179 & J. M. Cohen, ( NSW 1058823 ); 27 Sep. 2019 , M. A. M. Renner 9180 & J. M. Cohen, ( NSW 1058824 ); 27 Sep. 2019 , M. A. M. Renner 9181 & J. M. Cohen, ( NSW 1058825 ) .

Figures

Fig. 13. Pultenaea furcata (=P. sp. Dingo Creek (NSW 1058819)) line drawing (a) habit, (b) flowering branch detail, (c) flower, side view, (d) standard petal, (e) keel, (f) wing, (g) flower side view, petals removed, (h) magnified calyx, side view, (i) stem detail showing stipule, (j) ovary detail, (k) leaf, abaxial surface, (l) leaf, adaxial surface, (m) leaf-surface detail, abaxial, (n) leaf-surface detail, adaxial. Scale bar: 26.7 mm (a); 10 mm (b); 8 mm (c–g); 4 mm (h); 2.7 mm (i, j), 5 mm (k, l); 1.6 mm (m, n). All from NSW 1058832, a, i from dried material, b–m from spirit.

Fig. 14. Pultenaea furcata (= P. sp. Dingo Creek (M. A. M. Renner 9176 & J. M. Cohen)) photos. (a–c) Shoots showing the production of buds and flowers in a dense inflorescence that terminates the shoot, note the dense covering of spreading hairs on the calyx, and the linear, inrolled leaves bearing a faint glaucouswash on their adaxial surface.(d) Dehisced pods,note the glabrous outer surface of thepod,and the absence of vegetative growth at the shoot apex post-flowering. (e) A terminal cluster of flowers with the faint red nectar-guides, and splayed wings over the greenish-yellow keel, note the concave, more-or- less cordate standard. (f) A shoot terminated by a dense cluster of flower buds. (g) Dehisced seed pods. All from the population in the upper reaches of Dingo Creek in the vicinity of voucher NSW 1058819.