Pultenaea mutabilis var. angusta 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 : 257-261

4b. Pultenaea mutabilis var. angusta M.A.M.Renner, P.H.Weston, & S.Clarke , var. nov.

Pultenaea sp. Newnes ( I. R. Telford 5072 & M. D.Crisp) NSW Herbarium, PlantNet [https://plantnet.rbgsyd.nsw.gov.au/ accessed 22 Feb. 2022].

Type: New South Wales, Central Tablelands, Wollemi National Park , eastern side of Canobala Creek , on ledge 200 m above stream, 726 m, 33°08′37.2S 150′13′43.1′E, 10 Oct. 2019, M.A.M. Renner 9164 & S. Clarke (holo: NSW 1058833 , iso: CANB, MEL).

Diagnosis

Pultenaea mutabilis var. angusta differs from P. mutabilis var. mutabilis in its linear leaves that are 0.4–1.0 (average 0.7) mm wide.

Erect single- or multi-stemmed woody shrub up to 4 m tall, stems up to 4 cm in diameter at chest height; bark grey–brown, smooth to weakly fissured at trunk base, irregularly branched, not whorled, sometimes main branches bifurcate with numerous shorter secondary branches. Branching is initially alternate, which is best expressed within leafy shoot sectors; branches fawn–grey; branchlets yellow-green, dull; ridged by a trace running basally from the leaf insertion, yellow–green, sparsely hairy. New growth often distinctly bronzed. Stipules wine-purple, ageing to tan, then black; furcate, lobes long and narrow, straight, not recurved away from the stem, rather they are appressed and straight, or nearly so, most of the time; broadly inserted on the stem, insertion extending at an angle across and down the stem surface, recurved sometimes from the triangular leaf insertion scar; stipule lobes thickened medially like the leaf apex, basal lamina small, keeled medially where the lobe thickening extends through it; lamina margin irregular, with poorly formed projections. Leaves linear, 6.1–18.3 (average 11.1) mm long, 0.4–1.0 (average 0.7) mm wide, inrolled and channelled but dorsal surface visible, discolourous, dull green with only a hint of glaucous bloom above, brighter green below; apex tapered to a short point, red–brown; abaxial surface sparsely and continuously hairy from base to apex, hairs antrorse and usually appressed but sometimes tending to spread, variable in length; adaxial surface green with glaucous bloom, and small cutaneous papillae; abaxial cell surfaces with low, even, granular ornamentation. Leaf anatomy with ventral epidermis hyaline, pigmented hyalodermis absent, but orange-pigmented cells are scattered throughout the spongy mesophyll; three vascular traces are present, medial largest, not separated from epidermis by inflated cells. Inflorescence without evidence of internode compression, flowers in axils of normal vegetative leaves, which occur throughout flower-bearing portion of stem, which continues vegetative growth after flower production; stipules associated with flowers are shorter and wider than sterile leaf stipules. Flowers pedicellate, pedicel bearing sparse, short hairs; a cluster of orange–red brown glandular trichomes present in the leaf axil at the base and either side of the pedicel. Calyx cream–green suffused with red or red–purple, lobes green with dark bronze margins; at maturity may be glabrous or bear a few short hairs on the tube, but always bears long hairs along the midline of each lobe, usually extending below the sinus; the calyx-pedicel junction bears short hairs; when in bud calyx continuously clothed in hairs. Bracteoles wine-purple, triangular, apex not attenuate, shorter or longer than adjacent calyx sinus vertex. Corolla orange–yellow with faint blood-red semi-circular and radiating nectar guides at base of standard; keel orange–yellow; standard transversely elliptic to slightly obcordate, folded, not flat, at flower maturity; wings laterally splayed, asymmetrically obovate, upper margin straight, apex curved, sharper through upper half, auricle triangular, with a rounded to acute apex; keel asymmetrically elliptic, upper margin linear, lower margin continuously curved, deepest at mid point, apex broadly rounded, basal auricle triangular, acute. Anthers cream to pale lemon, filaments translucent. Ovary glabrous, style translucent, with short antrorse hairs on ventral surface immediately above ovary. Pods ~ 5 mm long ( Fig. 21 , 22 ).

Distribution and ecology

The distribution of Pultenaea mutabilis var. angusta follows the western edge of the Higher Blue Mountains sandstone plateau, from the headwaters of Rocky Creek on the northern side of Newnes Plateau in the south to the south-eastern side of Mount Coricudgy in the north. Throughout this distribution, P. mutabilis var. angusta is associated with the western cliff lines of the Narrabeen Group sandstone exposures, where it may grow in steep gully heads, on steep rocky hillsides, gullies between pagodas, or on ledges. Pultenaea mutabilis var. angusta grows in both forest, mallee, and shrubland communities, including dry sclerophyll woodland with Angophora bakeri , Eucalyptus piperita and Eucalyptus macrorhyncha ; tall Eucalypt forest containing Eucalyptus oreades and Eucalyptus piperita , with scattered rainforest species including Elaeocarpus reticulatus ; on the edge of rainforest; and in mixed shrubbery including Acacia echinula , A. obtusifolia , Boronia pinnata , B. rubiginosa , Conospermum sp. , Dillwynia sp. , Isopogon dawsonii , Grevillea mucronata , Lepidosperma sp. , Leptospermum polygalifolium , L. trinervium , L. macrocarpum , Leucopogon affinis , Styphelia mutica , Persoonia levis , P. linearis , Xanthorrhoea sp. and Zieria cytisoides . The sites on which P. mutabilis var. angusta occurs vary in aspect from south-east through west to north, suggesting the species is tolerant of a wide range of exposures. Soils are generally sandy loams, and may be derived in part from claystone. Flowers are scented with a fragrance remarkably like vanilla ice-cream.

Recognition

Pultenaea mutabilis var. angusta can be recognised by the irregular branching architecture, wherein inflorescences are produced on shoots that continue vegetative growth and so do not affect architecture. The flowers are produced in the axils of leaves that are identical to those on vegetative shoot sectors, and the internodes separating sequential flowers are the same length as those separating sterile leaves. The stipules in both flowering and sterile shoot sectors are short and narrow, with narrow, straight lobes. The branchlets bear short antrorse hairs. The leaves are narrow linear (0.4–1.0 mm wide) and bear antrorse hairs on the abaxial surface, the cells of which are bulging, not mamillose, and bear fine granular ornamentation. This combination of characters should prevent confusion with other members of the P. glabra complex, and most other Pultenaea species. When sterile, and in the herbarium, P. mutabilis var. angusta could be confused with P. furcata , but the latter has prominent triangular mamillae on the abaxial leaf surface that are conspicuous when leaves are examined under magnification even in dried material.

Variation

Pultenaea mutabilis var. angusta expresses variation in several characters, including the relative lengths of calyx lobes, sometimes the medial ventral lobe is longer than the other two ventral lobes, the length of the bracteoles relative to the calyx, which may be shorter than or equal to the adjacent sinus in length, and the hairiness of leaves, which vary from nearly hairless to sparsely hairy through their whole length. Variation in leaf hairiness is expressed by every individual we have examined.

Conservation status

Pultenaea mutabilis var. angusta may qualify for listing as Endangered under the IUCN criteria. The distribution from Newnes State Forest and the Wolgan Valley in the south to at least Mount Coricudgy in the north suggests an extent of occurrence less than 5000 km 2. The taxon occurs in highly fragmented and local sites, and usually, but not always, occurs in association with Mount York claystone, on ledges below this formation. The taxon may experience extreme fluctuations in response to fire events, if its susceptibility to fire is similar to other members of the P. glabra complex, including P. mutabilis var. mutabilis . However, the resprouting capacity of P. mutabilis var. mutabilis is unknown, as is the distribution of this taxon between the northern and southern known occurrences, within the largely unmodified area encompassed by Wollemi National Park in between, and as a result its likely area of occupancy and extent of occurrence are difficult to estimate without further survey work.

Etymology

From the Latin angusta, narrow, in reference to the linear leaves, which present the sharpest point of distinction from the typical variety.

Specimens examined

NEW SOUTH WALES. Central Tablelands: Wollemi National Park : 2.7 km SE of Mt Coricudgy, 27 Oct. 1976, I. R. H. Telford 5072 & M . D. Crisp, ( NSW 459587 ); ~ 40 km NNE of Lithgow, 2.5 km SSW of Glen Davis, Green Gully , 25 Oct. 1976, I. R. H. Telford 5024 & M . D. Crisp, ( NSW 459588 ); ~ 1.5 km N of Newnes, ~ 23 km E of Capertee , divide between Little Capertee and Canobla Creeks, 14 Oct. 2015, S. Clarke 687, ( NSW 933340 ); ~ 30 km N of Lithgow, ~ 4.5 km SW of Newnes, gully draining narrow divide between Wolgan and Capertee valleys, 30 Sep. 2015, S. Clarke 674, ( NSW 934288 ); ~ 30 km N of Lithgow, ~ 5 km S of Newnes, cliffs flanking western side of Wolgan Valley , 30 Sep. 2015, S. Clarke 669, ( NSW 934285 ); Running Stream Creek, ~ 3 miles [~ 5 km] ENE of Glen Davis (~ 30 miles [~ 48 km] SE of Rylstone , 25 Sep. 1964, E. F. Constable 5098, ( NSW 82528 ); Glow Worm tunnel area, Wolgan Valley , 3 Oct. 1993, H. Brian s.n., ( NSW 398520 ); Halfway between car park and Glow Worm Tunnel (upper end), Wolgan Valley , Oct. 1995, H. Brian s.n., ( NSW 398519 ); ~ 3 km N of Newnes, ~ 22 km E of Capertee cliffs, overlooking an un-named tributary of Canobla Creek , 14 Oct. 2015, S. Clarke 680, ( NSW 933341 ); 14 Oct. 2015, S. Clarke 681, ( NSW 933342 ); 14 Oct. 2015, S. Clarke 682, ( NSW 933343 ); 14 Oct. 2015, S. Clarke 683, ( NSW 933344 ); 14 Oct. 2015, S. Clarke 684, ( NSW 934280 ); 14 Oct. 2015, S. Clarke 685, ( NSW 934281 ); 14 Oct. 2015, S. Clarke 686, ( NSW 934282 ); eastern side of Canobola Creek , on ledge 200 m above stream bed, 10 Oct. 2019, M. A. M. Renner 9164 & S . Clarke , ( NSW 1058833 ); 10 Oct. 2019, M. A. M. Renner 9165 & S . Clarke , ( NSW 1058834 ); 10 Oct. 2019, M. A. M. Renner 9166 & S . Clarke , ( NSW 1058835 ); 10 Oct. 2019, M. A. M. Renner 9167 & S . Clarke , ( NSW 1058836 ); 10 Oct. 2019, M. A. M. Renner 9168 & S . Clarke , ( NSW 1058837 ); 10 Oct. 2019, M. A. M. Renner 9169 & S . Clarke, ( NSW 1058838 ); Wolgan Valley, track to Glow Worm tunnel, from Wolgan Valley Road via Old Coach Road , 7 Oct. 2019, M. A. M. Renner 9162, ( NSW 1058831 ); 7 Oct. 2019, M. A. M. Renner 9163, ( NSW 1058832 ); Newnes State Forest: track leading to Rocky Creek tributary, 15 May 1990, G. D’Aubert 733 & K . Marriott, ( NSW 227748 ) .

Figures

Fig. 21. Pultenaea mutabilis var. angusta (= P. sp. Newnes (I. R. Telford 5072 & M. D. Crisp)) line drawing. (a) Habit, (b) flowering branch detail, (c) flower, side view, (d) standard petal, (e) flower, side view, petals removed, (f) wing, (g) keel, (h) ovary detail, (i) calyx, side view, (j) stem detail showing stipule, (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); 2.7 mm (h, j); 4 mm (i); 5 mm (k, l); 1.6 mm (m, n). All from NSW 1058831, a from dried material, b–m from spirit.

Fig. 22. Pultenaea mutabilis var. angusta (= P. sp. Newnes (I. R. Telford 5072 & M. D. Crisp)) photos. (a) Habit showing irregular branching pattern, and flowers scattered among the leaves. (b) A flowering shoot showing the scattered flowers, produced in association with normal vegetative leaves. (c) Close- up of a shoot apex showing the narrow filiform stipule lobes and hairy stem surface. (d) Flowers showing the yellow keel and splayed wings. (e) Shoot showing the linear leaves with a glaucous bloom on the adaxial surface. (f–g) Close-up flowers showing the calyx that appears glabrous, but which actually bears short hairs, the papery bracteoles, and the yellow keel. All from NSW 1058831.