Daviesia microcarpa Crisp (1995: 1211)

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

3. Daviesia microcarpa Crisp (1995: 1211) . Type [approximate locality data given because the species is rare]: Western Australia, Coolgardie, near Norseman , 32°10’S, 121°50’E, M. D. Crisp 5943, J. Taylor & R. Jackson, 19 September 1979. Holotype: CBG; isotypes: CBG, K, NSW, PERTH

A MONOGRAPH OF DAVIESIA

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CRISP ET AL.

Sprawling shrubs with many long, weak, tangled stems, to 0.4 m tall and 1 m broad, mostly glabrous but vegetative parts with scattered minute resinous warts, grey-green. Root anatomy normal (unistelar). Branchlets ascending, angular-terete with raised ribs. Phyllodes crowded (2.5–3.5 per cm), divaricate, needle-like, terete and smooth when fresh, angular with ribs when dry, apically pungent, basally articulate, 8–20 mm long, 0.5–0.75 mm diam., midrib more prominent on adaxial surface. Unit inflorescences 1 or 2 per axil, 1(2)-flowered; peduncle 0.5–1.5 mm long; subtending bracts oblong, clasping the pedicel, ca. 0.75–1 mm long. Pedicels ca. 1 mm long. Calyx ca. 3 mm long including the ca. 1 mm stipitate receptacle to which it is abruptly contracted; lobes ± equal, triangular, straight, acute, apiculate, ca. 0.5 mm long. Corolla : standard ovate, emarginate, auriculate, ca. 4–5 × 5 mm including the ca. 1 mm claw, centrally channelled, orange with pinkish red on veins and towards centre; wings obovate, rounded and incurved at apex, scarcely overlapping, auriculate, with a lobe opposite the auricles on the abaxial margin, ca. 4– 4.5 × 1.5 mm including the ca. 1.5 mm claw, pinkish red with orange tips; keel half transversely ovate with a scarcely acute apex, auriculate, saccate, ca. 3.5–4 × 1.5 mm including the ca. 1.5 mm claw, pale orange-pink. Stamens strongly dimorphic: inner whorl of 5 with terete filaments and subversatile anthers with confluent thecae; outer whorl of 5 with broad compressed filaments and basifixed 2-celled anthers; filaments cohering. Pod obliquely very broadly to shallowly obtriangular, ± obtuse, 4–4.5 × 3–3.5 mm, with raised reticulate venation; upper suture sigmoid; lower suture acute. Seed broadly obovoid, very small, ca. 2 mm long, 1.5 mm broad, 0.8 mm thick, yellow-brown with black mottling; aril ca. 0.8 mm long. ( Fig. 4 ).

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

Distribution:— Western Australia, known only from two disjunct populations, near Norseman and Southern Cross.

Habitat:— Grows on sand under Eucalyptus L’Héritier de Brutelle (1789: 18) or Allocasuarina Johnson (1982: 73) in shrubland with Triodia .

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

Selected specimens (6 examined):— Approximate locality data are given because the species is rare. WESTERN AUSTRALIA. Coolgardie: Type population near Norseman, M . I .H. Brooker 6429, 21 August 1979 ( CANB, PERTH); ibid., D. J . E . Whibley 4593, 29 October 1974 ( AD, PERTH); near Southern Cross , 31°10’S, 119°20’E, M . D. Crisp 9697 & L . G . Cook, 3 September 2004 ( CANB, PERTH) .

Affinity:— The molecular phylogeny ( Fig. 1A ) indicates that D. microcarpa has no close relative. The small sizes of the flowers and pods distinguish this species from nearly all its congeners: the pods are the smallest in the genus and only D. ulicifolia and D. arthropoda sometimes have similarly small flowers. Daviesia arthropoda and D. ulicifolia are easily distinguished by their horizontally flattened, well-spaced phyllodes, spinescent branchlet tips and larger pods (7.5–8 mm long). Daviesia microcarpa is most similar to D. ulicifolia subsp. stenophylla in coastal northern New South Wales and Queensland. As well as similar floral size and fruiting morphology, these taxa have 1-flowered inflorescences in common. However, the phyllodes of D. ulicifolia subsp. stenophylla are trigonous in cross-section, the habit is open and divaricate, the branchlets are spinescent, the standard lacks auricles and has a claw nearly as long as the lamina, and the pod is acute. Daviesia genistifolia is also very similar but can be distinguished by its well-spaced phyllodes, 2–6-flowered racemes and zygomorphic calyx with the upper two lobes united into a lip. It does not occur west of the Flinders Ranges in South Australia.

III. Actinomorphic Calyx Clade

Figures

FIGURE 1A. Phylogeny (part) of Daviesia estimated using maximum likelihood (PHYML) from concatenated sequences of ITS (nrDNA), and ndhF and trnL–trnF (cpDNA). The tree was rooted using the monotypic sister groups Viminaria and Erichsenia (not shown). The informal clade names are used for reference in the taxonomic treatment. Numbers on branches show non-bootstrap support. The tips are labelled with the taxon name and sample accession number.

FIGURE 4. Daviesia microcarpa. A. Flowering branchlet. B. Inflorescence (1-flowered). C. Pod. A from Brooker 6429; B from Crisp 5943 (type); C from Whibley 4593. Drawn by A.L. Prowse. Adapted from Crisp (1995) with permission from CSIRO Publishing.