Daviesia suaveolens Crisp (1991a: 269)

Crisp, Michael D., Cayzer, Lindy, Chandler, Gregory T. & Cook, Lyn G., 2017, A monograph of Daviesia (Mirbelieae, Faboideae, Fabaceae), Phytotaxa 300 (1), pp. 448-450 : 448-450

46. Daviesia suaveolens Crisp (1991a: 269) , Crisp (1995: 1239), Crisp (2002: 524). Type: New South Wales, South Coast, Merricumbene area, M.D. Crisp 4654, 16 November 1978. Holotype: CBG; isotypes: AD, K, MEL, MO, NSW, PERTH

Arborescent shrubs or small, olive-like trees, to 6 m tall, glabrous. Root anatomy unknown. Branchlets ascending or arching, terete, slightly angular. Phyllodes scattered, erect to lax, narrowly obovate or rarely linear, ± straight, apex obtuse or rounded, occasionally retuse, rarely acute, tapered to the obscurely articulate base, 30–100 × 4–17 mm, with midrib and main lateral veins visible, dark green to glaucescent, sometimes discolorous. Unit inflorescences 1 or 2 per axil, condensed-racemose and appearing umbellate, 3–6-flowered; peduncle from almost nil to ca. 0.5 mm long; rachis 1–2 mm long; barren basal bracts appressed, overlapping and mostly concealing the inflorescence rachis; subtending bracts appressed, narrowly oblong, with margins incurved around pedicel and occasionally fimbriate, 1–1.5 mm long. Flowers very fragrant. Pedicels 1–3 mm long. Calyx 4–5 mm long including 1–1.5 mm stipe-like receptacle, pale green with a purple tinge in the sinuses, sometimes also at apices; upper 2 lobes united into a truncate, emarginate lip ca. 1.5 mm long; lower 3 lobes triangular or broadly triangular, ca. 1 mm long. Corolla : standard transversely broadly elliptic, emarginate, truncate or broadly cuneate at base, 8–9 × 9–10 mm including 1.5–2 mm claw, pure yellow or with faint red markings surrounding an intensely yellow bilobed marking at centre; wings obovate, rounded and strongly incurved at apex, enclosing the keel, auriculate, 7– 8 × 3–3.5 mm including 2–2.5 mm claw, yellow; keel half very broadly obovate, scarcely acute, auriculate, saccate, 5.5 × 2–2.5 mm including 2–2.5 mm claw, pale yellow or with pink infusion towards apex. Stamens strongly dimorphic: inner whorl of 5 with longer, terete filaments and globose, subversatile anthers with confluent thecae; outer whorl of 5 with shorter, compressed filaments and obloid, ± basifixed, 2-celled anthers; filaments free, about equal in length. Pod obliquely shallowly obtriangular, acute with a short beak, compressed, 9–12 × 6–7 mm, greenish or pale brown; upper suture sigmoid; lower suture acute. Seed ellipsoid, 3–3.5 mm long, 1.5–2 mm broad, 1.25 mm thick, tan with black markings; aril narrowly obloid, with a thick, ridged lobe, 2–2.5 mm long. ( Fig. 45 ).

Flowering period:— September to November. Fruiting period: January and February.

Distribution:— Southern New South Wales, along the eastern escarpment of the tablelands, from Monga south to Bemboka.

Habitat:— Grows on razorback ridges and precipitous upper slopes in skeletal acidic soils, often among boulders. The sites are mostly very exposed but receive a great deal of moisture from rain and fog. Associated vegetation is usually open Eucalyptus forest dominated by ash species such as E. sieberi Johnson (1962: 125) , with Acacia and ferns as the principal understorey elements.

Selected specimens (27 examined):— NEW SOUTH WALES. Southern Tablelands: Nelsons Creek Fire Trail, 36°31’S, 149°37’E, G. A . Butler 1367, 2 February 1984 ( CBG); Wadbilliga Trig Trail , 36°24’S, 149°38’E, M . D. Crisp 1247, 30 September 1975 ( AD, BISH, CBG, MEL, NSW); 9 km ESE of Araluen , 35°41’S, 149°54’E, M . D. Crisp 2308, 16 November 1976 ( AD, BISH, CBG, K, L, MEL, NSW, PERTH); near Dampier Trig , 36°02’S, 149°40’E, M . D. Crisp 2387, 1 December 1976 ( AD, BRI, CBG, NSW, PERTH, US); 11.5 km S of Monga , 35°41’S, 149°54’E, M . D. Crisp 2434 & L . D. Williams, 13 January 1977 ( AD, CBG, MEL, NSW); 8.2 km NNW of

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Mt Donovan , 35°47’S, 149°52’E, M . D. Crisp 4660, 16 November 1978 ( CBG, NSW); 10 km NNE of Bemboka , 36°33’S, 149°35’E, I. R . Telford 8897, 12 January 1983 ( CBG); 24 km SSE of Braidwood , 35°38’S, 149°53’E, M . D. Crisp 7190 & G. A . Butler, 1 December 1983 ( CBG, MEL, MO); 11 km S of Monga , 35°41’S, 149°54’E, J. M . Taylor 2638 & I. R . Telford, 1 November 1989 ( CBG, HO, MEL, NSW) .

Affinity:— Daviesia suaveolens shows an obvious relationship to the widespread and variable D. mimosoides

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CRISP ET AL.

but can be distinguished by several characters taken together. The characteristic sweet smell of the flowers of D. suaveolens differentiates it from D. mimosoides . This odour is so strong that it permeates the forest when plants of D. suaveolens are flowering. In D. mimosoides , the flowers have a fainter odour that is not especially pleasant. However, these odours are lost from pressed and dried specimens.

The calyx of D. suaveolens is longer and narrower than that of D. mimosoides . Its lower 3 lobes are triangular or broadly triangular (length: breadth> 1) and 0.8–1 mm long, whereas in D. mimosoides they are shallowly to very shallowly triangular (length: breadth <0.6) and 0.3–0.6 mm long. In addition, the lower 3 calyx lobes of D. mimosoides are markedly thickened and tinged with dark brown at the apices whereas those of D. suaveolens are uniform in thickness and colour. Some differences can also be perceived between the inflorescences of these two species. In D. suaveolens , the inflorescence is small, compact and subumbelliform, with three to six flowers and a short rachis (1–2 mm long) that is mostly concealed by the overlapping bracts. The inflorescence of D. mimosoides is usually more diffuse, being corymbiform, and has five to ten flowers and a longer rachis (3–15 mm long) with well-spaced bracts. Partial exceptions to this distinction are some specimens of D. mimosoides from higher elevations in southern New South Wales and eastern Victoria in which the inflorescence is condensed like that of D. suaveolens . However, the number of flowers per inflorescence is high (6 or more) as in typical D. mimosoides .

Other distinctions between D. suaveolens and D. mimosoides are found in the habit and the colour of the petals. Mature plants of D. suaveolens are small trees up to 6 m tall, resembling olive trees when open-grown. This species is among the tallest in the genus, exceeded only by D. arborea and D. laxiflora . By contrast, plants of D. mimosoides are usually multi-stemmed shrubs less than 3 m tall, though young or exposed plants of D. suaveolens are shrubby and plants of D. mimosoides in a few localities are arborescent. The petals of D. suaveolens are pure yellow with faint red markings at the centre of the standard. By contrast, the standard of D. mimosoides is orange-yellow at the edges with a conspicuous dark red marking towards the centre and the wings are mostly dark red.

Populations of D. mimosoides and D. suaveolens grow in close proximity apparently without interbreeding. In general, D. suaveolens occurs on sites that experience higher rainfall and are more exposed, rockier and better drained than those where D. mimosoides is found.

Figures

FIGURE 45. Daviesia suaveolens. A. Flowering branchlet. B. Inflorescence. C. Flower with subtending bract. D. Calyx opened out, upper lobes at left. E. Standard. F. Wings. G. Keel. H. Same, opened out. I. Pod. A from Crisp 4654 (type); B, I from Crisp 1247; C–H from Crisp 2308. Drawn by A.L. Prowse. Adapted from Crisp (1991a) with permission from CSIRO Publishing.