A Taxonomic Revision of Mezoneuron (Leguminosae: Caesalpinioideae: Caesalpinieae) Author Clark, Ruth P. text Phytotaxa 2016 2016-09-14 274 1 448 450 http://dx.doi.org/10.11646/phytotaxa.274.1.1 journal article 10.11646/phytotaxa.274.1.1 1179-3163 13657001 7. Mezoneuron latisiliquum (Cavanilles) Merrill Phillip. J. Sci. 4. Bot.: 268. 1907 . Type:— PHILIPPINES , Luzon, Cavanille’s plate excl. leaves, which are bauhinioid, Epitype (here designated):— PHILIPPINES , Luzon, Albay Province , Cuming 1193 , K (K000980294!); isoepitypes K (K000980295!), L (L0651597!) . Basionym: Bauhinia? latisiliqua Cav. Icones et Descriptiones Plantarum vol. 5. 1799. Synonym. Caesalpinia latisiliqua (Cav.) Hattink. Reinwardtia 9(1): 37. 1974 . Synonym. Caesalpinia torquata Blanco. Fl. Filip. : 336. 1837. Type: lost fide Hattink 1974 . Synonym. Mezoneurum procumbens Blanco. Fl. Filip. II : 235. 1845 . Type: lost fide Hattink 1974 . Synonym. Mezoneuron rubrum Merr. Publ. Bur. Sci. Gov. Lab. 6: 7. 1904 . Type:— PHILIPPINES , Paragua (= Palawan ), Point Separation, 20 Feb. 1903 , Merrill 805 , K (K000264162!), PNH†, US . Synonym. Mezoneuron platycarpum Merr. Phillip. J. Sc., Bot. 11: 85. 1916 . Type:—BORNEO, Sarawak , Baram District, Miri River, Jan. 1895 , Hose 70 , BM!, K (K000264166!), L (L0018788!), PNH. Synonym. Mezoneuron cabadbarense Elmer. Leafl. Phillip. Bot. 10: 3757. 1939 . Type:— PHILIPPINES , Mindanao, Cabadbaran, Jul. 1912 , Elmer 13386 , BM!, BO, F!, GH, K (K000264161!), L!, P, PNH, NY (0004516!), U. Synonym. Mezoneuron balansae Prain ex Gagnep. Fl. Gén. Indoch. 2: 198. 1913 . Lectotype :—INDO-CHINA: Tonkin , pres de Luang Yen , Aug. 1885 , Balansa 1298 , P (barcode unknown); isolectotypes K (K000264169!), L (L0018786!, L0018787!), Hattink 1974 . Synonym. Mezoneuron keo Gagnepin. Bull. Mus. Hist. Nat. Par. 2: 318. 1952 . Type :—INDO-CHINA, Annam , Tourane , Jun. 1920 , Poilane 1452 . Holotype P; isotypes K (K000264168!), L (L0018785!). Synonym. Mezoneuron oxyphyllum Gagnepin. Bull. Mus. Hist. Nat. Par. 2: 319. 1952 . Type:— VIETNAM , Annam, N’ghe-an, reserve for. de Co-ba , Fleury, F . for Chevalier , 32512 . Holotype P (P 02142678 !); isotype P (P 02142677 !). Woody climber or scandent shrub to 20 m in length. Stems with scattered recurved prickles, sometimes with corky spine-tipped tubercles on older stems; glabrous, or sparsely whitish to orange tomentose. Stipules oblong or linear, 16 • Phytotaxa 274 (1) © 2016 Magnolia Press CLARK sometimes with acuminate apex, or triangular, 1–2 × 1–5 mm , glabrous or partially tomentose. Leaves with 3–9 pairs pinnae; 3–8 pairs leaflets per pinna; petiole 3.5–12 cm ; leaf rhachis 12–50 cm , recurved prickles usually present, paired at pinna insertion points, and sometimes also scattered on the internodes; pinnae (4–) 6–12 (–13) cm; pinna rhachis sometimes with recurved prickles paired at leaflet insertion points and sometimes also scattered on the internodes; leaf rhachis, petiole, and pinna rhachis glabrous, or sparsely, occasionally moderately, whitish to orange tomentose. Leaflets alternate to subopposite; the terminal leaflets 2–7.8 × (1–) 1.9–5.2 cm , obovate, base oblique, apex rounded to retuse with small mucro; lateral leaflets 1.5–7.5 × 0.7–3.8 (–4.6) cm, elliptic to oblong or slightly obovate, base oblique, apex rounded to retuse, mucronulate; all leaflets with upper surface glabrous or very sparsely tomentose, sometimes hairs only on margins, lower surface glabrous, or sparsely to moderately tomentose, or with semi-appressed hairs, sometimes hairs only at base or margins; 2˚ venation anastomosing, 3˚ venation reticulate, veins visible on both surfaces, distinctly raised below, midvein sunken above, raised below. Inflorescence a raceme or panicle, terminal or axillary, up to 100 cm long, the axis to 0.6 cm diameter at base, axes sparsely to moderately whitish or golden or orange tomentose; recurved prickles occasionally present on basal portion of peduncle; pedicels (8–) 10–25 mm , not articulated; sparsely to densely pale orange to golden tomentose, or glabrous. Bracts caducous, semicircular, 1 × 1–3 mm , sparsely tomentose; bracteoles caducous, broadly elliptic, acuminate, 1.5–3 × 0.5–1 mm , margins or entire outer surface orange tomentose, apex glabrous. Flowers with an asymmetric hypanthium, 4–6 × (6–) 8–12 (–15) mm; lower calyx lobe highly cucullate, [7–] 11–19 × 6–8 mm ; other lobes elliptic to ovate, [4–] 5–10 × 3–5 mm ; hypanthium and calyx both glabrous to moderately to densely golden or orange tomentose. Median petal strongly bilobed, to ⅓ or ½ of length, inrolled laterally, (8–) 11–17 × (8–) 11–13; glabrous. Upper lateral petals obdeltate, apex rounded or acuminate, 2–5 × 2–3 mm , glabrous. Lower lateral petals obdeltate, apex rounded or acuminate, 2–5 × 2–3 mm , glabrous. Stamen filaments flattened, (8–) 11–31 mm , sparsely to densely orange villous, along the basal ¼–⅔, on inner surface or on margins only; anthers 1–3 mm . Ovary 4–10 mm long, style 8–20 mm long, ovary and style glabrous, or partially, or sparsely to densely golden or orange sericeous, hairs sparser towards apex of style; stigma laterally positioned, narrowly cupular 0.25–1 mm wide, the rim papillate. Fruit : pedicel in fruit to 30 mm , sometimes with a swelling 8–10 mm below hypanthium; elliptic, base oblique, apex with wing extending to form a beak, or occasionally emarginate at apex of midvein; wider part of the persistent, asymmetric hypanthium below winged side of fruit; 8.5–16.5 × 3–5.5, wing 7–15 mm wide; fruit surface glabrous, or sparsely to moderately orange tomentose, sometimes partially; venation reticulate, raised and visible on fruit body, anastomosing and slightly visible on the wing. Seeds 6–9 (–13) per fruit; elliptic, visible in outline on fruit exterior when mature, glossy, dark brown, ca. 9–12 × 6–7 × 1 mm . Distribution :— Vietnam , Borneo, Philippines , Sulawesi, Papua New Guinea . ( Fig. 8 ). FIGURE 8. Distribution of M. latisiliquum in South East Asia, showing specimens with hairy (circles) and glabrous (triangles) ovaries. Habitat and ecology :—Foothill forest; lowland rainforest; alluvial forest; riparian forest; swamp forest; primary and secondary forest; roadsides in open places; coastal vegetation; substrate sandstone, limestone, or shale. Elevation 0–1500 m . A TAXONOMIC REVISION OF MEZONEURON Phytotaxa 274 (1) © 2016 Magnolia Press • 17 Phenology :— Vietnam : flowering May–June, fruiting June–December. Malesia : flowering and fruiting throughout the year. Preliminary conservation assessment :—Extent of Occurrence 6,601,692.749 km 2 = LC; Area of Occupancy 388.000 km 2 = EN. Category Assigned :—Least Concern (LC). Taxonomic notes :—The type of M. latisiliquum is an illustration of a specimen that bears the leaves of a species of Bauhinia . An epitype is here selected with a leaf representative of M. latisiliquum . The epitype also bears flowers, that are absent from the type illustration. The ovary indumentum of this species is very variable, ranging from glabrous to partially to densely hairy. The leaflets also vary considerably in size, from 1.5 to nearly 8 cm in length, and 1 to ca. 5 cm in width. The patterns of variation correlate with locality ( Fig 8 ).