Mezoneuron schlechteri (Harms) R. Clark

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

21. Mezoneuron schlechteri (Harms) R. Clark in Clark, R. & Gagnon, E. Phytotaxa 207(1): 68–92. 2015.

Type:— NEW CALEDONIA: Auf den Bergen bei Oubatche, 800m, 26 Deca. 1902, Schlechter, F.R.R. 15572 (fl.).

Lectotype:—M (M0217766, image!); isolectotypes:—BR, (000005110605, image!), K (K000556378!), L (L0018794!), Clark & Gagnon 2015.

Basionym. Caesalpinia schlechteri Harms. Beiträge zur Kenntnis der Flora von Neu-Kaledonien. Botanische Jahrbücher für Systematik, Pflanzengeschichte und Pflanzengeographie: 1–274. 1906.

Liana to 20 m or more in length. Stems unarmed, or with scattered recurved prickles, glabrous or sparsely to densely ferruginous tomentose. Stipules semi-persistent, triangular, 0.5–1 × 0.5–1 mm, subglabrous to sparsely tomentose. Leaves with (2–) 3–7 (–8) pairs pinnae; (3–) 4–8 (–14) pairs leaflets per pinna; petiole 2–5.5 (–8) cm; leaf rhachis (3–) 5–23 cm, unarmed, or with recurved prickles up to 5 mm in length, in pairs at pinna insertion points and scattered on the internodes; pinnae 2.8–12.7 cm; leaf rhachis, petiole sparsely to moderately (sometimes patchily) ferruginous pilose or tomentose, pinna rhachis glabrous to moderately (occasionally densely) ferruginous pilose or tomentose. Leaflets opposite, elliptic to rhomboid, strongly oblique at base, apex obtuse to retuse; the terminal leaflets 2–4.7 × 0.6–3.1 cm; lateral leaflets 1.8–4.4 × 0.6–2.3 cm; 2˚ veins anastomosing, 3˚ veins reticulate, veins clearly visible on both surfaces, or indistinct on upper surface; upper surface usually glossy, glabrous, or sometimes with a few hairs at the base or along the basal part of the margins, lower surface glabrous, with sometimes a few hairs at the base or along the basal part of the margins. Inflorescence a raceme or panicle, axillary, supra-axillary or terminal, 13–31 cm long, glabrous, or sparsely to moderately ferruginous tomentose on all parts, occasionally a few recurved prickles on the basal portion of the peduncle. Pedicels 3–10 mm, not articulated, glabrous to densely ferruginous tomentose. Bracts sometimes present, triangular, 0.5–2 × 0.5–1 mm, subglabrous to sparsely tomentose; bracteoles usually caducous, lanceolate, inrolled, 1–1.5 × 0.5–1 mm, sparsely to moderately orange pubescent, or with hairs only along margin, sometimes glabrescent. Flowers with a

A TAXONOMIC REVISION OF MEZONEURON

Phytotaxa 274 (1) © 2016 Magnolia Press • 37 hypanthium 1–2 mm deep, glabrous, lower calyx lobe ca. 8 × 3–4 mm, other lobes ca. 6 × 3–4 mm, all lobes glabrous or with hairs on margins. Median petal 4–6 × 1.5–3 mm, with a circular patch of dense, dark ferruginous hairs on inner surface between claw and blade, and hairs on margins of claw, outer surface glabrous. Upper lateral petals elliptic to slightly obovate, (4–) 5–8 × 1.5–3 mm, blade glabrous, claw very sparsely ferruginous tomentose on inner surface. Lower lateral petals elliptic to slightly obovate, (4–) 5–8 × 1.5–4 mm, blade glabrous, claw very sparsely ferruginous tomentose on inner surface. Stamen filaments 5–11 mm long, the basal ⅓ to ½ with long translucent or ferruginous tomentose hairs; anthers ca. 1 mm long. Ovary 3–4 mm long, glabrous, style 5–7 mm long, sparsely to moderately pale translucent or ferruginous tomentose on lower half, sometimes thickening towards apex; stigma funnel-shaped, the rim papillate. Fruit elliptic, the base cuneate, apex acute or the wing extending to form a short beak; 4–5.6 × 1.7–2.6 cm, wing 4–6 mm wide; fruit surface glabrous; venation reticulate, raised and visible on the fruit body, no veins visible on the wing; hypanthium persistent. Seeds 1 per fruit, suborbicular, not or faintly visible in outline on fruit exterior when mature.

Distribution:—Endemic to New Caledonia. Grande Terre , North and South Province, East to West (primarily East). ( Fig. 24).

Habitat and ecology:—Dense wet forest, on ultramaphic and non-ultramaphic (volcano-sedimentary) soil. Elevation 100–800 m.

Phenology:—Flowering July–January, fruiting December–February

Preliminary conservation assessment:—Extent of Occurrence 10,382.55 km ² = VU; Area of Occupancy 84.00 km² = EN.

Category assigned:—Least Concern (LC). This species does not seem directly threatened. (RLA Flore NC 2016).