Daviesia crassa Crisp (1995: 1183)

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

128. Daviesia crassa Crisp (1995: 1183) . Type [approximate locality data given because the species is rare]: Western Australia, Avon , SW of Harrismith, 33°S, 117°40’E, M. D. Crisp 5531, 28 January 1979. Holotype: CBG, 2 sheets; isotypes: K, L, NSW, PERTH

Compact dense shrubs to 1.8 m high, glabrous, glaucous to pruinose. Root anatomy with anomalous secondary thickening (cord type). Branchlets spreading to ascending, usually flexuose with crowded phyllodes, smooth when fresh, longitudinally wrinkled when dry; occasional shoots are long and straight with scattered slender phyllodes. Phyllodes crowded (rarely scattered), erect, thick, clavate (rarely linear-fusiform), terete, apically acuminate, pungent, tapering to the articulate base, 10–40 mm long, 2–6 mm diam., appearing succulent but filled with pith, smooth when fresh, longitudinally wrinkled when dry. Seedling phyllodes flattened at nodes 1–3, becoming terete by node 10. Unit inflorescences 1 per axil, racemose, 3–5(–8)-flowered,; peduncle 3.5–6 mm long; rachis 4–11 mm long; subtending bracts appressed, ovate, ca. 0.5–1 mm long. Pedicels gently dilated upwards, 2–4 mm long. Calyx narrowly campanulate, 4–5 mm long including 2–2.5 mm stipe-like receptacle; upper 2 lobes united in a truncate,

A MONOGRAPH OF DAVIESIA

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CRISP ET AL.

emarginate lip, ca. 1 mm long; lower 3 minute, deltoid, ca. 0.5 mm long. Corolla pure yellow; standard very broadly ovate, emarginate, margins recurved, slightly cordate, 4–4.5 × 5.5–6 mm including the ca. 0.5 mm claw; wings spathulate, with lower margins divergent and apices rounded and incurved but not overlapping, scarcely auriculate, ca. 4.5 × 2.5 mm including the 1 mm claw; keel half depressed-obovate, scarcely acute, auriculate, saccate, ca. 4.5 × 2 mm including the 1.5 mm claw. Stamens weakly dimorphic and ca. uniform in length; inner whorl of 5 with slender, angular filaments and shorter anthers; outer whorl of 5 with broader, compressed filaments and longer anthers; filaments free; anthers all basifixed and 2-celled except vexillary anther versatile with confluent thecae. Pod obliquely shallowly obtriangular, beaked, compressed, ca. 20 × 7 mm; upper suture undulating; lower suture scarcely acute. Seed not seen. ( Fig. 129 ).

Flowering period:— Only specimen flowering in January. Fruiting period: One specimen seen fruiting in September.

Distribution:— Western Australia, south-central wheatbelt, between Wagin and Harrismith.

Habitat:— Grows in white, sometimes gravelly, sand over laterite, in undulating terrain in kwongan heath.

Conservation status:— National: Not listed. WA: Priority 4, adequately known and near-threatened or not threatened, requiring regular monitoring.

Additional specimens examined:— Approximate locality data given because the species is rare. WESTERN AUSTRALIA. Avon : SW of Harrismith, 33°S, 117°40’E, L. R . Frizell s.n. & K . Morrison, 4 August 1964 ( PERTH 5200539 ); ibid., M . D. Crisp 5533, 28 January 1979, seedling ( CBG); ibid., M . D. Crisp 6147 et al., 26 September 1979 ( CBG, PERTH); near Wagin, 33°20’S, 117°20’E, Cronin s.n., 1890 ( MEL 81103 and 81105); source of the Blackwood River , 33°40’S, 116°50’E, Cronin s.n., 1889 ( MEL 81106 ) .

Affinity:— This bizarre plant looks more like a member of the Crassulaceae than a legume. However, the thick, club-shaped phyllodes are filled with dry pith, not with succulent tissue. No other Daviesia could be confused with this species. There is, however, an apparent relationship with D. pachyphylla , which also has thick, pith-filled phyllodes, as well as similar inflorescences and flowers. Daviesia pachyphylla is readily distinguished by the phyllodes diverging at 90° from the branchlet and not tapering to the base, the slightly larger flowers (e.g. standard 7–8 mm broad) with intense maroon markings on the petals, and the more or less equilateral pods. Moreover, D. pachyphylla has an open, spindly habit.

Figures

FIGURE 129. Daviesia crassa. A. Flowering branchlet. B. Inflorescence. C. Pod. A, B from Crisp 5531 (type); C from Crisp 6147. Drawn by A.L. Prowse. Adapted from Crisp (1995) with permission from CSIRO Publishing.