Libidibia (DC.) Schltdl., in Linnaea 5: 192. 1830, descr. emended E. Gagnon & G. P. Lewis

Gagnon, Edeline, Bruneau, Anne, Hughes, Colin E., de Queiroz, Luciano Paganucci & Lewis, Gwilym P., 2016, A new generic system for the pantropical Caesalpinia group (Leguminosae), PhytoKeys 71, pp. 1-160 : 61-63

19. Libidibia (DC.) Schltdl., in Linnaea 5: 192. 1830, descr. emended E. Gagnon & G. P. Lewis Figs 31 , 32

Caesalpinia section Libidibia DC. (1825).

Stahlia Bello (1881), syn. nov.

Diagnosis.

Libidibia is related to Hoffmannseggia , Stenodrepanum , Balsamocarpon and Zuccagnia but differs in being a genus of medium to tall trees, 6-20 m in height (versus woody based perennial herbs to shrubs, 10 cm to 5 m tall), most species have a distinctive, smooth patchwork bark in shades of white, grey and green ("snake skin bark") a characteristic not found in the other four genera. Libidibia (except Libidibia monosperma ) has bipinnate leaves ( Balsamocarpon and Zuccagnia are pinnate) and coriaceous or woody, glabrous, eglandular, indehiscent fruits which dry black (red in Libidibia monosperma ) versus thick, turgid, glandular, resinous, indehiscent fruits ( Balsamocarpon ), or laterally compressed, gall-like,?indehiscent fruits covered in trichomes ( Zuccagnia ). Stenodrepanum and Hoffmannseggia are bipinnate but the fruits of most species of Hoffmannseggia are dehiscent with twisting pod valves and persistent sepals (in Libidibia sepals are caducous in fruit); the fruits of Stenodrepanum are narrow, cylindrical and torulose.

Type.

Libidibia coriaria (Jacq.) Schltdl. ≡ Poinciana coriaria Jacq.

Emended description.

Small to medium-sized or large unarmed trees, 6-20+ meters in height; bark hard, smooth, with a patchwork of shades of grey, white and pale green, often referred to as snake skin bark, (except in Libidibia coriaria and Libidibia monosperma , where it is rough and fissured). Stipules not seen. Leaves alternate, bipinnate and ending in a pair of pinnae plus a single terminal pinna, rarely pinnate ( Libidibia monosperma ); pinnae (in bipinnate species) in 2-10 opposite pairs, plus a single terminal pinna; leaflets opposite, in 3-31 pairs per pinna, ovate, elliptic to oblong, apex rounded, mucronate or acute, base often oblique, subcordate, rounded or obtuse, eglandular or with subsessile gland dots on the undersurface of the blades, on either side of the midvein, glabrous to occasionally puberulous; in bipinnate leaves the leaflets (3-) 4-31 × 2.5-14 mm; in pinnate leaves, leaflets are much larger, c. 40-90 × 15-35 mm. Inflorescences terminal or axillary racemes or panicles, sometimes corymbose, with pedicellate flowers. Flowers bisexual, zygomorphic; calyx comprising a hypanthium and 5 sepals, the lower sepal slightly longer and cucullate in bud, caducous, but hypanthium persisting as a calyx ring around the pedicel as pods mature; petals 5, free, yellow or white, the median petal sometimes flecked or blotched orange or red; stamens 10, free, pubescent on the lower half of the filaments, eglandular (except for Libidibia ferrea , which has stipitate glands); ovary eglandular, glabrous or pubescent. Fruit coriaceous to woody, oblong-elliptic to suborbicular, straight (contorted in Libidibia coriaria ), indehiscent, eglandular, glabrous, black (red and somewhat fleshy in Libidibia monosperma ), 15-80 × 10-30 mm. Seeds oblong to elliptic, somewhat laterally compressed, smooth.

Geographic distribution.

A genus of ten taxa in seven species in the Neotropics. One species in Mexico, one widespread in Brazil, one in Colombia, Venezuela and the Antilles, one in Colombia, Ecuador and Peru, one in Paraguay, Bolivia, Argentina and SW Brazil, one ( Libidibia monosperma , previously in the monospecific genus Stahlia ) endemic to Puerto Rico and the Dominican Republic, and Libidibia coriaria widespread throughout Mexico, Central America, the Caribbean and NW South America. Other species perhaps waiting to be discovered and described, both in the field and in herbaria; the genus needs revising.

Habitat.

Seasonally dry tropical forest and thorn scrub (including Brazilian caatinga) and savanna woodland. Libidibia monosperma occurs along the margins of mangrove swamps and in marshy deltas, in drier edaphic conditions.

Etymology.

The name Libidibia is derived from the vernacular name ‘libi-dibi’ or ‘divi-divi’ used for some species.

References.

Britton (1927); Britton and Rose (1930: 221, 318-319); Burkart (1936, Caesalpinia melanocarpa : 78-82); Macbride (1943, Caesalpinia paipai : 193-194); Little and Wadsworth (1964); U.S. Fish and Wildlife Service (1995); Ulibarri (1996); De Queiroz (2009: 130-133); Borges et al. (2012); Barreto Valdés (2013).

Figures

Figure 31. Libidibia coriaria. A inflorescences and foliage B leaflet undersurface showing glands C flower D calyx opened out E median petal F detail of glands on back of median petal G upper lateral petal H lower lateral petal I stamen J gynoecium K stigma L fruit M seed. A-C from Hughes 1495 D-M from Macqueen 8. Drawn by Eleanor Catherine.

Figure 32. Libidibia monosperma (Tul.) E. Gagnon & G. P. Lewis. A fruits and foliage (M. F. Gardner, Dominican Republic, Gardner & Knees 7027 (E )) D inflorescence (Carlos Pacheco, Wikicommons (https: // commons. wikimedia. org / wiki / File: Stahlia _ monosperma _ flower _ (5840542648). jpg), Puerto Rico, USA, unvouchered). Libidibia paraguariensis (D. Parodi) G. P. Lewis B unripe fruits (C. E. Hughes, Santa Cruz, Bolivia, Hughes 2475 (FHO )). Libidibia glabrata (Kunth) C. Cast. & G. P. Lewis C fruits K inflorescence (C. E. Hughes, La Libertad, Peru, Eastwood et al. RJE 85 (FHO )). Libidibia coriaria (Jacq.) Schltdl. E flowers (C. E. Hughes, Esteli, Nicaragua, MacQueen 8 (FHO )) F branch with fruits (C. E. Hughes, Metapan, El Salvador, Lewis 1745 (K )) I bark (C. E. Hughes, Oaxaca, Mexico, Hughes 1933 (FHO )). Libidibia sclerocarpa (Standl.) Britton & Rose, G inflorescence (C. E. Hughes, Oaxaca, Mexico, Lewis 1800 (K )) H bark (C. E. Hughes, Oaxaca, Mexico, Hughes et al. 1494 (FHO )). Libidibia ferrea var. parvifolia (Benth.) L. P. de Queiroz J inflorescence (G. P. Lewis, Bahia, Brazil, unvouchered).