Daviesia dilatata Crisp (1995: 1187)

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

101. Daviesia dilatata Crisp (1995: 1187) . Type: Western Australia, Roe, 80 km NE of Ravensthorpe , 33°08’S, 120°41’E, M. D. Crisp 6037, J. Taylor & R. Jackson, 21 September 1979. Holotype: CBG; isotype: PERTH

Open shrubs to 1 m high, glabrous, grey-green to glaucous. Root anatomy unknown. Branchlets gently flexuose, terete to bluntly trigonous in cross-section, smooth when fresh, striate when dry. Phyllodes scattered, ascending, ± decurved, vertically dilated, often strongly sickle-shaped, sometimes subulate and divaricate or gently recurved, very rigid, tapered to a conspicuously black pungent apex, shortly decurrent at the broad base, 7–50 mm long, 2–8 mm broad, smooth when fresh, striate when dry. Unit inflorescences condensed, cluster-like racemes, 3–8- flowered; peduncle up to 0.5 mm long; rachis 1–2 mm long; subtending bracts spreading, spathulate, apex fimbriate, ca. 1 mm long. Pedicels 1–3.5 mm long. Calyx rather narrow, 4–5 mm long including the ca. 1.5 mm attenuate receptacle; lobes recurved; upper 2 lobes united into a truncate, emarginate lip, ca. 1 mm long; lower 3 lobes triangular, acuminate, ca. 0.75 mm long. Corolla : standard transversely elliptic, emarginate, strongly recurved, 6–6.5 × 6–7.5 mm including the 1.5–2 mm claw, mostly orange with a red central ring around a yellow centre; wings obovate with a rounded, incurved apex enclosing the keel, auriculate, 6–6.5 × 2.25–3 mm including the 2–2.5 mm claw, dark crimson; keel half transversely broadly elliptic, incurved with an acute apex, auriculate, saccate, 5–6 × 2 mm including the 2–2.5 mm claw, dark crimson. Stamens strongly dimorphic: inner whorl of 5 with longer filaments and round, versatile anthers with confluent thecae; outer whorl of 5 with shorter filaments and oblong, basifixed, 2-celled anthers; filaments cohering. Pod obliquely shallowly obtriangular, acute, compressed, 7–8 × ca. 5 mm, red-brown; upper suture sigmoid; lower suture obtuse. Seed not seen. ( Fig. 102 ).

Flowering period:— August and September. Fruiting period: September and October.

Distribution:— Western Australia, southern-most Avon, Eyre and Roe Districts, from Nyabing south to near Bremer Bay and east to Mt Ragged.

Habitat:— Occurs in sandy, and occasionally gravelly soil on flat terrain, in low heath to tall shrubland with mallee Eucalyptus spp. dominating the overstorey.

Selected specimens (23 examined):— WESTERN AUSTRALIA. Avon: Nyabing, eastern edge, 33°33’S, 118°09’E, M . D. Crisp 5204, 16 January 1979 ( CBG, PERTH); 10 km from Nyabing along road to Katanning , 33°35’S, 118°03’E, M . D. Crisp 5198, 16 January 1979 ( AD, CBG, MEL). Roe : 11 km E of Gnowangerup, 33°57’S, 118°06’E, K . Newbey 442, 9 September 1962 ( PERTH); 32 km SW of Newdegate , E boundary of Reserve no. 29023, 33°19’S, 118°47’E, J. M . Koch N130 , 16 January 1979 ( PERTH); ca. 90 km NE of Ravensthorpe, 9 km SW of Welcome Soak , 33°05’S, 120°46’E, M . D. Crisp 6035, et al., 21 September 1979 ( CBG, PERTH). Eyre : 1.56 km SW of Mt Desmond, 33°37’S, 120°09’E, M . D. Crisp 8989 & W . Keys, 20 October 1996 ( CBG, PERTH); 34 km W of Bremer Bay , ca. 34°24’S, 119°03’E, J. W . Green 4839, 23 August 1978 ( PERTH); Fitzgerald River National Park, 31 km S of Ravensthorpe along road to Hamersley River estuary, 33°49’S, 119°55’E, M . D. Crisp 5008, 10 January 1979 ( CBG); 33.5 km N of Hopetoun along road to Ravensthorpe , 33°40’S, 120°06’E, P. S . Short 2685, et al., 4 September 1986 ( CBG, MEL, PERTH); 3 km WNW of Cape Riche, near Cheyne Inlet , 34°36’S, 118°45’E, M . D. Crisp 5105, 14 January 1979 ( CBG, PERTH) .

Affinity:— This species presents an obvious similarity to both D. decurrens and D. pectinata , and has been confused with them. In the fresh state, both may be distinguished from D. dilatata by the striations and ridges along their phyllodes and branchlets. In particular, the decurrent phyllode-bases make the cross-section of the branchlets sharply triquetrous. When dry, D. dilatata is lightly striate, but neither ridged or ribbed, and the cross-section of the branchlets is bluntly trigonous (immediately below the phyllodes) or terete (lower down). The phyllodes of D. decurrens and D. pectinata are not as frequently or strongly decurved as in D. dilatata . A well-developed raceme-rachis further distinguishes D. pectinata , and striate bracts further distinguish D. decurrens .

This species is also similar to D. subulata , which differs in having exclusively subulate phyllodes, whilst the upper two calyx lobes are not united in a truncate lip and the lower three lobes flare outwards.

228 • Phytotaxa 300 (1) © 2017 Magnolia Press

CRISP ET AL.

Figures

FIGURE 102. Daviesia dilatata. A. Flowering branchlet. B, C. Phyllode variation. D. Inflorescence. E. Pod. A, D from Crisp 6037 (type); B from Crisp 5204; C from Green 4839; E from Crisp 5105. Drawn by B-J. Osborne. Adapted from Crisp (1995) with permission from CSIRO Publishing.