Mezoneuron furfuraceum Wallich ex Prain J. As. Soc. Beng.

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

10. Mezoneuron furfuraceum Wallich ex Prain J. As. Soc. Beng. 11, 66: 471. 1897. ( Prain 1897b).

Type :— MYANMAR, Tennasserim , Martaban , Attran River, Wallich cat. n. 5835. Holotype K (K000264175!); isotype BM (BM000958805!)

Paratypes:— MYANMAR, Pegu, Makhoye Hill, King’s collectors s.n .; SRI LANKA: “Ceylon”, Thwaites 3601 (location of these specimens unknown).

Based on Caesalpinia furfuracea Wall., Wallich cat. n. 5835, 1831–32 (nomen).

Synonym. Caesalpinia furfuracea (Prain) Hattink. Reinwardtia 9(1): 1–69. 1974.

Woody climber or scrambling shrub, height unknown. Stems with scattered recurved prickles up to 5 mm long; sparsely, sometimes irregularly, whitish to orange tomentose. Stipules persistent, ellipsoid, sometimes with acuminate apex, ca. 0.5 × 1–3 mm, glabrous to moderately tomentose, or on margins only. Leaves with 6–10 pairs pinnae; (5–) 7–11 pairs leaflets per pinna, petioles 2–6 cm; leaf rhachis 9.5–29 cm, paired recurved prickles on

20 • Phytotaxa 274 (1) © 2016 Magnolia Press

CLARK rhachis at pinna insertion points, and usually scattered on the internodes; pinnae 4.5–11.5 cm, pinna rhachis with single prickle at the apex, ca. 1 mm; leaf rhachis, petiole, and pinna rhachis sparsely or moderately whitish or orange tomentose. Leaflets opposite or subopposite; the terminal leaflets obovate, base oblique, apex rounded, obtuse or retuse, 1.8–2.9 × 0.8–1.3 cm; lateral leaflets oblong to slightly obovate, base oblique, apex rounded, obtuse to retuse, mucronulate, 1.5–2.8 × 0.6–1.1 cm; all leaflets with upper surface glabrous, lower surface glabrous apart from a few tomentose hairs around the base and along the midvein; 2˚ venation anastomosing, 3˚ venation reticulate, veins faintly visible on both surfaces, or not visible. Inflorescence a raceme or panicle, axillary or terminal; sometimes with scattered recurved prickles on axes; axes glabrous or sparsely to moderately tomentose; pedicels 17–34 mm, articulated 2–4 mm below the hypanthium, glabrous. Bracts caducous, sometimes present, semicircular, 1 × 1 × 2 mm, glabrous or the margins tomentose; bracteoles caducous, narrowly lanceolate, 7–12 × 1 mm, sparsely tomentose with pale orange hairs. Flower s with an asymmetric hypanthium, 2–4 × 6–8 mm; lower calyx lobe highly cucullate, ca. 10–15 × 4–8 mm, other lobes ca. 6–8 × 3–6 mm; hypanthium and calyx glabrous. Median petal strongly reflexed backwards, laterally inrolled, with a circular patch of dense orange hairs on inner surface between claw and blade, outer surface glabrous or both surfaces glabrous if from the Lesser Sunda Islands, 4–10 mm long, blade 4–5 mm × 5–6 mm, claw 3–6 mm long. Upper lateral petals ovate to orbicular, blade 9–12 × 10–20 mm, claw ca. 1 mm long, glabrous. Lower lateral petals ovate to orbicular, blade 12–14 × 11–14 mm, claw 1–2 mm, glabrous. Stamens filaments flattened, 14–20 mm long, moderately orange villous on the basal ⅓ to ½ on inner surface; anthers 2–4 mm. Ovary 7–10 mm long, style 9–20 mm long, thickened towards apex; both glabrous, stigma funnel-shaped, ca. 1.5 mm wide, the rim slightly papillate. Fruit oblong-elliptic, base cuneate to rounded, sometimes oblique, apex cuneate to acute, sometimes with the central vein extending to form a beak; 12.5–20.5 × 4–6.6 cm, wing 10–18 mm wide; the persistent, asymmetric hypanthium wider below winged side of fruit; fruit surface glabrous, with a waxy whitish coating; venation reticulate, raised and visible on the fruit body, anastomosing and not or slightly visible on the wing; hypanthium persistent. Seeds 3–4 per fruit; elliptic, spaced ca. 1 cm apart, close to the central vein and more or less perpendicular to it, visible in outline on fruit exterior when mature, ca. 11 × 6 × 4 mm, brown, smooth, dull.

Distribution:— Myanmar, Thailand, Laos, Lesser Sunda Islands ( Fig. 11).

Habitat and ecology:—Open alluvial thicket along stream; mixed evergreen and deciduous forest; savannahs; scrub; rugged limestone terrain; sandy loam soil. Occurs in regions that experience a dry season. Elevation to 1000 m. ( Fig. 11).

Phenology:— Myanmar: flowering December, fruiting December–February. Thailand:

August–November, fruiting January–April. Lesser Sunda Islands: flowering May–June, fruiting July.

flowering

A TAXONOMIC REVISION OF MEZONEURON

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Preliminary conservation assessment:—Extent of Occurrence 1,669,797.015 km 2 = LC; Area of Occupancy 44.000 km 2 = EN.

Category assigned:—Least Concern (LC).