Daviesia obovata Turczaninow (1853: 261)

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

82. Daviesia obovata Turczaninow (1853: 261) , Bentham (1864: 77), Crisp (1995: 1217). Type: ‘Drum. V. n. 41.’ Holotype: KW; isotypes: E, FI-W, G (2 sheets), K (3 sheets), MEL, OXF, P, W

Slender, erect shrubs, to 1.5 m high, glabrous, glaucous. Root anatomy with anomalous secondary thickening (cord type). Branchlets erect, terete, becoming angular towards the apex, longitudinally wrinkled when dry. Phyllodes scattered, erect, obovate, apically rounded and ± retuse, base constricted and petiole-like, obscurely articulate, (40–)55–90 × (8–) 18–45 mm, venation prominent and reticulate when dry, thick and fleshy when fresh, wrinkled when dry. Unit inflorescences 1 per axil, racemose, 2–3-flowered; peduncle 2.5–7 mm long; rachis 5–7 mm long, ending in a sterile bristle ca. 3 mm long with barren bracts at the apex; subtending bracts spreading, ± oblong, cupped, ca. 4 mm long. Pedicel 3–4 mm long. Calyx 7–8 mm long in flower including the 1.5–2.5 mm receptacle, in fruit enlarged 2-fold and thickened, persistent black and conspicuous after fruit has fallen; lobes ± equal, upper 2 lobes united higher than the lower 3, ca. 2.5 mm long. Corolla : standard depressed-ovate, emarginate, 9.5–11 × 14.5–16 mm including the ca. 3 mm claw, yellow with a pale green ring around the yellow centre; wings obovate, apex rounded and incurved to enclose the top of the keel, auriculate, 9–10.5 × 3.5–4 mm including the ca. 2.5 mm claw, pale yellow-green, becoming pale, yellow-maroon towards the apex; keel half depressed-obovate, scarcely acute, auriculate, 7.5–9 × 3–3.5 mm including the 2–2.5 mm claw, pale yellow-green. Stamens strongly dimorphic: inner whorl of 5 with longer, slender, terete filaments and shorter, round, versatile anthers with confluent thecae; outer whorl of 5 with shorter, broader, compressed filaments and longer, oblong, basifixed, 2-celled anthers; filaments cohering. Pod obliquely very broadly to shallowly obtriangular, acute, compressed, 8.5–23 × 8.5–10 mm, abaxial margin bent through 180°, giving the pod an almost oblong appearance; upper suture sigmoid or deeply undulating; lower suture strongly acute. Seed fusiform, ca. 5 mm long, 2–2.5 mm broad, 1.5–2 mm thick, light brown with black mottling, no mottling when immature; aril ca. 3.5 mm long. ( Fig. 82 ).

Flowering period:— October. Fruiting period: Beginning in October.

Distribution:— Western Australia, restricted to two disjunct areas in the eastern Stirling Range and the Barrens.

Habitat:— Grows on meta-sandstone outcrops at moderate elevation (500–800 m) in heath dominated by Eucalyptus marginata or in pink-grey sandy loam with diverse shrubs including species of Allocasuarina , Proteaceae and Acacia .

Conservation status:— National: Endangered. WA: Endangered, Declared Rare Flora.

Additional specimens examined:— Approximate locality data are given because the species is rare. WESTERN AUSTRALIA. Eyre: Eastern Stirling Range , 34°20’S, 118°20’E, M . D. Crisp 8948 & W . Keys, 15 October 1996 ( CBG, PERTH); ibid., S . D. Hopper 2332, 7 May 1982 ( CANB, PERTH); ibid., A . Morrison 12607, 18 October 1902 ( AD, K, MEL, PERTH); ibid., J. S . Beard 7654, 4 October 1975 ( NSW, PERTH); ibid., A. S . George 10419, 11 October 1970 ( PERTH); ibid., M . D. Crisp 5289, 19 January 1979 ( CBG, K, MEL, PERTH) .

Affinity:— The peculiar calyx sets this species apart from all others in the genus except D. megacalyx . In both these species the calyx increases to twice its size from flower to fruit, hardening and turning black in the process. After the pods have dehisced and fallen, these old black calyces remain on the plant for a considerable period, giving the appearance of fruits from a distance. Daviesia megacalyx may be distinguished by its non-glaucous, much narrower phyllodes (5–12 mm broad), which are narrowly obovate or narrowly elliptic in outline, by the smaller, 1(2)-flowered racemes; and by the shorter flowering calyces (3.5–5 mm long).

A MONOGRAPH OF DAVIESIA

Phytotaxa 300 (1) © 2017 Magnolia Press • 187 188 • Phytotaxa 300 (1) © 2017 Magnolia Press

CRISP ET AL.

Figures

FIGURE 82. Daviesia obovata. A. Branchlet with persistent enlarged post-fruiting calyces. B. Lower phyllode, adaxial view. C. Inflorescence. D. Pod. A, B, D from Crisp 5289; C from George 10419. Drawn by B-J. Osborne.