Mezoneuron brachycarpum Bentham

Clark, Ruth P., 2016, A Taxonomic Revision of Mezoneuron (Leguminosae: Caesalpinioideae: Caesalpinieae), Phytotaxa 274 (1), pp. 448-450 : 448-450

18. Mezoneuron brachycarpum Bentham

Flora Australiensis (2): 278. 1864 (as Mezoneurum brachycarpum ).

Lectotype:— AUSTRALIA, New South Wales, Richmond River , C. Moore s.n., K (K000264179!), Hattink 1974

Remaining syntype:— AUSTRALIA, Queensland, Araucaria Range, Moreton Bay , F. Mueller s.n., K !

Original syntype:— AUSTRALIA, Queensland, Wide Bay , Bidwell s.n., K! (this specimen is re-identified as M. scortechinii F. v. Mueller)

Synonym. Caesalpinia brachycarpa (Benth.) Hattink nom illeg. non C. brachycarpa (A. Gray) Fisher. Reinwardtia 9: 53. 1974.

Synonym. Caesalpinia subtropica Pedley. Austrobaileya 1(1): 33. 1977. syn. nov.

Scrambling shrub or liana to 5 m in length. Stems with minute scattered recurved prickles to 2 mm; sparsely to moderately whitish to pale orange pilose or tomentose. Stipules persistent, triangular, 1–1.5 × 2 mm, sparsely to densely appressed-pilose. Leaves opposite, with (3–) 4–8 pairs pinnae; (3–) 5–7 pairs leaflets per pinna; petioles 1.4–5.4 cm; leaf rhachis 4.5–25 cm, with small recurved prickles in pairs at the pinna insertion points; pinnae subopposite, 2.2–7 cm; leaf rhachis, petiole, and pinna rhachis sparsely to moderately densely whitish to pale orange pilose or tomentose. Leaflets alternate; the terminal leaflets obovate, the base oblique, apex obtuse, rounded, or retuse, 0.8–2.1 × 0.5–1.1 cm; lateral leaflets elliptic to oblong, base oblique, apex obtuse, rounded, or retuse, 0.7–1.9 × 0.5–1.2 cm; all leaflets with upper surface glabrous or with sparse whitish appressed to patent or tomentose hairs, lower surface with sparse whitish appressed to patent or tomentose hairs; 2˚ venation anastomosing, 3˚ venation reticulate, veins faintly visible above, slightly raised below. Inflorescence a panicle to ca. 21 cm, the racemes opposite; terminal or axillary, with small, sometimes dense, recurved prickles scattered on the axes; moderately to densely whitish to pale orange tomentose; pedicels 3–5 mm (– 6 mm in fruit) long; articulated 1–2 mm below hypanthium; sparsely to moderately orange tomentose. Bracts persistent, triangular, 1–2 × 1–2 mm, sparsely to densely tomentose; bracteoles semi-persistent, broadly lanceolate, the apex acuminate, 2–4 × 1 mm, moderately to densely orange or golden tomentose on both surfaces. Flowers with a hypanthium 1 × 2–3 mm; lower calyx lobe 4–5 × 2 mm, other lobes 3–4 × 1–2 mm; hypanthium and all calyx lobes sparsely orange to golden tomentose (or hairs appressed), inner surface glabrous. Median petal oblong, laterally inrolled, ca. 4 × 2 mm, with circular patch of ferrugineous hairs on inner surface between claw and blade, claw with hairs on margins, outer surface glabrous. Upper lateral petals elliptic to obovate, 4 × 2–3 mm, including claw ca. 1 mm long, a few hairs on inner surface of claw, petal otherwise glabrous. Lower lateral petals elliptic to obovate, ca. 5 × 2–3 mm, including claw ca. 1 mm long, a few hairs on inner surface of claw, petal otherwise glabrous. Stamen filaments 4–6 mm long, tomentose on the basal ½; anthers ca. 0.75 mm long. Ovary ca. 2 mm long, style ca. 4 mm long, both glabrous; stigma cupular, the rim papillate. Fruit chartaceous, elliptic, base cuneate, apex acute, sometimes slightly beaked, 2.5–4.2 × 1.3–3 cm, wing 2–4 mm wide; fruit surface glabrous; venation reticulate, raised and clearly visible on fruit body, no veins visible on the wing; hypanthium persistent. Seeds 1 per fruit; large, flat, reniform, slightly visible in outline on fruit exterior when mature.

Distribution:—Endemic to Australia (New South Wales, Queensland). ( Fig 21)

Habitat and ecology:—Rainforest; secondary forest margin; savannah; roadside; sandy soil. Elevation 0–900 m.

Phenology:—Flowering July–November, fruiting November–January

Preliminary conservation assessment:—Extent of Occurrence 304,497.872 km 2 = LC; Area of Occupancy 228.000 km 2 = EN.

34 • Phytotaxa 274 (1) © 2016 Magnolia Press

CLARK

Category assigned:—Least Concern (LC).