Daviesia umbonata Crisp & Chandler (1997: 324)

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

36. Daviesia umbonata Crisp & Chandler (1997: 324) . Type: Western Australia, Avon, 4 km N of Moonijin , Dowerin –Cadoux railway line, 30°55’S, 117°06’E, M. D. Crisp 6686, 23 July 1980. Holotype: CANB; isotype: PERTH

Bushy, divaricate shrubs to 1 m high, muricate to hispid on branchlets, occasionally pedicels hispidulous. Root anatomy unknown. Branchlets ribbed, thickened at nodes. Phyllodes scattered, spreading at 45–90°, flat or slightly concave above, narrowly elliptic to narrowly ovate with an acuminate, pungent apex, basally cuneate (rarely rounded) with a thickened articulation, (7–)10–20(–25) × 2–5(–8) mm; dull green. Unit inflorescences 1 or 2 in the axils, 1-flowered; peduncle nil; subtending bracts spreading, obovate, ca. 1 mm long. Pedicels 3–4 mm long. Calyx 4–5 mm long including the 1–1.5 mm receptacle, with a small, dark callus just below each sinus (except between the upper 2 lobes) at the base of the calyx lobes; upper 2 lobes united in a truncate lip, 1–1.5 mm long; lower 3 lobes triangular, 0.5–1 mm long. Corolla : standard elliptic, emarginate, 6–9 × 6–7 mm including the 2–2.5 mm claw, calli ± indistinct, yellow with dark red infusion at the centre; wings elliptic with a rounded apex, auriculate, 7–8 × 2–3 mm including the 2–2.5 mm claw, dull red; keel half depressed-ovate, with an acute apex, sharply curved at base, with an angle of ca. 120° between claw and tip, slightly auriculate, 8–9 × 2–3 mm including the 3.5–4.5 mm claw, dull red. Stamens strongly dimorphic: inner whorl of 5 with longer, slender, terete filaments and globose,

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CRISP ET AL.

versatile anthers, thecae confluent; outer whorl of 5 with much shorter, broader, compressed filaments and longer, 2-celled, basifixed anthers; filaments free. Pod obliquely very shallowly obtriangular with an acuminate apex, 12– 14 × 6–8 mm, light brown with black mottling; upper suture sigmoid; lower suture acute. Seed ellipsoid, compressed vertically, 3.8–4 mm long, 2–2.4 mm wide, 1–1.4 mm thick, dark brown; aril ca. 1.7 mm long. ( Fig. 36G–J ).

Flowering period:— June and July. Fruiting period: July and August.

Distribution:— Western Australia, in the Wongan Hills and Manmanning area, and northward.

Habitat:— Growing in white slightly clayey sand. The vegetation is kwongan (heath) dominated by Callitris and Allocasuarina , with myrtaceous shrubs.

Selected specimens (9 examined):— WESTERN AUSTRALIA. Irwin: ‘ Bulma Road’, Walkaway, 28°56’S, 114°48’E, J. S . Beard 2515, 31 May 1963 ( PERTH); Tabletop Road , 24 km NE of Dongara, P . Roberts 800, 14 July 1988 ( PERTH); Howathana Road, Nanson , 28°33’S, 114°45’E, C. E . Woolcock D 35, 17 July 1981 ( CBG). Avon : 5 km NW of Wongan Hills, 30°50’S, 116°41’E, M . D. Crisp 6521, 17 July 1980 ( CBG); W of Wongan Hills , C. E . Woolcock D 90, 15 July 1981 ( CBG); Wongan Hills , 30°54’S, 116°43’E, C. E . Woolcock D13, 15 July 1981 ( CBG)

Affinity:— Daviesia umbonata is similar to D. cardiophylla , D. cunderdin and D. euryloba . The phyllodes of Daviesia umbonata are usually narrow, nearly flat and tapered to a cuneate or occasionally rounded base, unlike those of D. cardiophylla (ovate to very broadly so with a cordate base), D. cunderdin (with a rounded base and not usually narrow) and D. euryloba (folded upwards longitudinally and with a cuneate or rounded base). The calyx in D. umbonata has a small callus just below each sinus between adjacent calyx lobes, as in D. cunderdin , whereas D. cardiophylla normally lacks these calli. Despite the similarities between D. umbonata and D. cunderdin in leaf shape and calyx calli, the latter species clearly differs in petal characters. The flower of D. cunderdin is much larger (e.g. standard 12–15 mm long) and red. Also, the calli on the standard are distinctly deltoid appendages and much larger (0.6–0.7 mm high) than in D. umbonata . The keel of D. euryloba readily distinguishes it from D. umbonata , being sharply hooked inward towards the standard.

Hybrids:— Daviesia cardiophylla × D. umbonata . Some populations around the Wongan Hills area appear to be intermediate between D. umbonata and D. cardiophylla but typical populations of each species occur elsewhere in the district, which suggests that the intermediates represent occasional hybridisation between otherwise two distinct species and not a zone of introgression ( Crisp & Chandler 1997).

Figures

FIGURE 36. Daviesia cardiophylla species group. Daviesia cardiophylla. A. Flowering branchlet. B–D. Phyllodes, showing variation. E. Inflorescence (1-flowered) with calyx representing flower. F. Keel. Daviesia umbonata. G. Branchlet tip with pod. H. Phyllode. I. Keel. J. Pod. Daviesia cunderdin. K. Keel. Daviesia euryloba. L. Keel. M. Pod. A, B, E, F from Crisp 6604; C from Crisp 6151; D from Crisp 6507; G, H & J from Crisp 6686 (type); I from Woolcock D13; K from Marchant & Seabrook s.n. (PERTH 3705153); L from Woolcock D74; M from Crisp 6030 (type). Drawing by A.L. Prowse and M.D. Crisp. Adapted from Crisp (1995) with permission from CSIRO Publishing.