Daviesia mesophylla Ewart (1907: 38)

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

118. Daviesia mesophylla Ewart (1907: 38) , Crisp (1995: 1211). Type: West Australia, F. Mueller. Lectotype (Crisp 1995: 1211): MEL 79038 . Syntype: S. W . Australia,? F . Mueller ( MEL 79039 ); isosyntype or isolectotype: PERTH

Procumbent shrubs, to 1(–2) m across, glabrous, glossy dark green. Root anatomy with anomalous secondary thickening (cord roots). Branchlets spreading to ascending, terete, with sharp longitudinal ridges in vivo. Phyllodes irregularly spaced, divaricate to ascending, vertically compressed, narrowly obovate or linear, somewhat oblique with thickened margins and a central channel, apex acuminate, pungent, often slightly recurved, base truncate,

A MONOGRAPH OF DAVIESIA

Phytotaxa 300 (1) © 2017 Magnolia Press • 261 articulate, 7–15(–25) × 0.75–2 mm, venation obscure even when dry. Unit inflorescences 1(2) per axil, 1(2)- flowered; peduncle 0.5–5 mm long; rachis nil, except for the occasional terminal racemes, where it is ca. 0.5 mm long; subtending bracts ascending, oblong, ca. 0.5–1 mm long. Pedicels 4–5.5(–10) mm long. Calyx 4–4.5 mm long including the 1–1.5 m receptacle; upper 2 lobes united in a narrow emarginate lip, ca. 1.5 mm long; lower 3 lobes triangular, ca. 1–1.5 mm long. Corolla : standard depressed- to very broad-ovate, emarginate, 7.5–8 × 7.5–9 mm including the ca. 1 mm claw, with 2 prominent calli at the base of the lamina, yellow to orange with a dark red centre; wings elliptic with a rounded apex, auriculate, 6.5–7.5 × 2–2.5 mm including the ca. 1.5 mm claw, light red; keel half very broadly ovate with an acicular beak, slightly auriculate, ca. 7.5 × 2 mm including the 2.5–3 mm claw, cream-coloured. Stamens moderately dimorphic: inner whorl of 5 with longer, ca. terete filaments and shorter, versatile anthers; outer whorl of 5 with shorter, compressed filaments and longer, basifixed anthers; filaments cohering; anthers all 2-celled. Pod obliquely shallowly obtriangular, acute, ± turgid, 12–14.5 × 8–8.5 mm; upper suture almost straight; lower suture acute to 90°. Seed globose, 3.5–4 mm long, 2.7–3.2 mm broad, 2.5–3 mm thick, black with a pale brown background; aril ca. 2.5 mm long. ( Fig. 119 ).

Flowering period:— October to April. Fruiting period: September to January.

Distribution:— Stirling Range and near Denmark, Western Australia.

Habitat:— Gravelly sand (sometimes clayey) and rocky slopes with mallee-heath ( Eucalyptus marginata ), or in heath on wet peaty or clayey sand.

Conservation status:— National: Not listed. WA: Priority 2, possibly threatened or near-threatened but not yet adequately surveyed.

262 • Phytotaxa 300 (1) © 2017 Magnolia Press

CRISP ET AL.

Selected specimens (13 examined):— Approximate locality data are given because the species is rare. WESTERN AUSTRALIA. Darling: Denmark Shire , 34°50’S, 117°10’E, B. G . Hammersley 2158, 20 February 1999 ( CANB, DNK). Eyre: Stirling Range , 34°30’S, 118°10’E, M . D. Crisp 5257, 18 January 1979 ( AD, CBG); Chester Pass , 34°20’S, 118°20’E, A. R . Fairall 1420, 2 April 1964 ( PERTH); Stirling Range , 34°30’S, 118°10’E, M . D. Crisp 6119, et al., 24 September 1979 ( CBG, MEL, PERTH); Stirling Range , 34°20’S, 118°20’E, M . D. Crisp 5273, 18 January 1979 ( AD, CBG, K, NSW, PERTH) .

Affinity:— This distinctive species is superficially similar to D. polyphylla and D. microphylla , but may be distinguished from both by its procumbent habit and summer flowering, and from D. microphylla by its non-spinescent branchlets. From D. preissii , which also flowers in summer, it is distinguished by its sharp stem ridges and by its procumbent habit.

Variation:— Plants from the Denmark area have a more slender appearance with longer stems, more widely spaced, longer (to 25 mm) phyllodes, and longer peduncles and pedicels, than those in the Stirling Range.

Figures

FIGURE 119. Daviesia mesophylla. A. Flowering branchlet showing procumbent habit. B. Phyllode. C. Inflorescence (1-flowered). D. Pod. A–C from Crisp 5273; D from Crisp 5257. Drawn by A.L. Prowse.