Chloroleucon foliolosum (Benth.) G.P.Lewis
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Authors
Rupert C. Barneby
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Authority
Barneby, Rupert C. & Grimes, James W. 1996. Silk tree, guanacaste, monkey's earring: a generic system for the synandrous Mimosaceae of the Americas. Part I. Abarema, Albizia, and allies. Mem. New York Bot. Gard. 74: 1-292.
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Family
Mimosaceae
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Scientific Name
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Type
"Banks of the Capibamba [probably = Capiberibe] in Pernambuco, Gardner, Villa do Barra [on Río São Francisco near 11°S in NW Bahia], Blanchet, no. 3136." — Lectotypus, Blanchet 3136, K(herb. bentham.)!; isotypi, †B = F Neg. 1196, NY!. —The syntype, Gardne
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Synonyms
Pithecellobium oligandrum Rizzini, Calliandra aristulata Rizzini
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Description
Species Description - Drought-deciduous, microphyllidious arborescent shrubs 3-8(-10) m with smooth trunks attaining 3 dm diam and stiffly flexuous, fuscous or castaneous, lenticellate annotinous branchlets, either unarmed or randomly armed at nodes with at first setiform but early lignescent and vulnerant, solitary or paired thorns to ±1 cm (mostly shorter), the lf-axes, lft-margin and often one or both faces of the thin-textured, subconcolorous lfts puberulent-pilosulous with incurved- ascending hairs to 0.15-0.25 mm but sometimes glabrous overall, the small hemispherical capitula of white or greenish white, often fragrant fls arising singly or rarely geminate from the axil of coevally expanding lvs on short-shoots; perulate buds narrowly ovoid compressed 2-4 mm, the castaneous striate scales glabrous dorsally, microscopically ciliolate. Stipules usually obsolete, exceptionally developed, then membranous oblanceolate to 5(-?) mm, caducous long before maturity of associated If. Lf-formula v—vii/( 15—) 17—27; lf-stk of longer lvs at maturity 3.5-6 cm (often shorter at anthesis), the longer interpinnal segments 5-9(-10) mm; nectary situated near or well below midpetiole, sessile or almost so, shallowly cupular 0.2-0.5(-0.6) mm diam, in profile 0.2-0.5 mm tall, a similar but smaller one at tip of lf- stk and yet smaller ones at tip of pinnae; pinnae decrescent toward base of lf-stk, thence subequilong, the rachis of longer ones 15-34 mm, the longer interfoliolar segments 0.5-1.1 mm; lfts decrescent only at extremities of pinnae, the rest subequilong, at first forwardly imbricate but spreading in age, in outline linear-oblong or very narrowly elliptic-oblong from auriculate base, at apex either obtuse or subacute, the larger ones 2.7-4.5(5) x (0.6)0.7-1.3 mm, 3.2-5 times as long as wide; venation of 3 (and sometimes a very short posterior fourth) primary nerves from pulvinule, the subcentric midrib flanked on each side by a weak intramarginal nerve produced almost to apex of blade and connected to them by 1 or 2 transverse secondary venules, the whole venation immersed above, pallid and finely prominulous beneath. Peduncles 8-19 mm; capitula 12-21-fid, the receptacle, including pedestal of terminal fl, 2-4 mm, the fls heteromorphic, the peripheral ones either sessile or very shortly pedicellate, the terminal one always sessile, a little stouter but hardly longer, its androecium much modified; bracts minute, membranous, very early caducous; PERIPHERAL FLS: perianth 5- merous, either glabrous or the calyx thinly puberulent externally, the corolla-lobes papillate-ciliolate; calyx membranous campanulate 0.9-1.7 x 0.6-0.8 mm, the depressed-deltate teeth 0.1-0.2 mm; corolla 3.2-5.2 mm, the lance-ovate lobes often unequal, 0.7—2 x 0.4-1 mm; androecium commonly 10-12-, rarely 20- merous, 10-14.5 mm, the tube 1.5—3.5 mm, always a trifle shorter than corolla; TERMINAL FL: calyx 1-2 x 0.8-1.3 mm, the teeth to 0.2 mm; corolla 4-7 mm; androecium 5.5—8.5 mm, the tube exserted from corolla, 5.5—8.5 mm, dilated and fimbriate at apex, the fertile stamens as in the peripheral firs; ovary truncate glabrous; style not dilated at apex, the stigma ±0.1 mm diam. Pods usually solitary, in profile broad-linear from narrowly cuneate base, ±8.5-14 x 1.3-2.4 cm, averaging wider (1.8-2.4 cm) in Argentina than in Bahia (mostly 1.3—1.8 cm) but not otherwise different, evenly recurved through ¼ to a full circle (but not spirally contorted), sometimes also randomly horizontally twisted, 14-19-seeded, the sutures 2-5 mm wide framing the at first plane, either green, brown or fuscous, stiffly leathery or eventually fibrous-woody, transversely venulose valves, these becoming low- convex over seeds and shallowly cross-sulcate between them, the mesocarp mealy, somewhat thickened; dehiscence inert, through both sutures, and the valves tending to crack between seeds (but not dissolved into free-falling segments), the seeds transverse in separated locules; ventral suture often undulate, but deeply constricted only where seeds abort, the dorsal (concavely arched) suture more evenly decurved; seeds (few seen) in broad view oblong- elliptic ±7-8.5 x 4.5-6 mm, the testa smooth, tan, somewhat fuscous-shadowed beneath a hippocrepiform pleurogram ±4.5-5 x 2-3 mm.
Distribution and Ecology - In caatinga woodland, spiny shrub thickets, and short-tree forest of "chaco" type, mostly at 400-700 m but lower in the Pantanal of SW Brazil, of bicentric range in extra-Amazonian tropical South America: best known from E Brazil, between 6° and 15°S from S Ceará and W Pernambuco to S-centr. Bahia; and scattered within 15°-23°S on the upper Paraná in Mato Grosso do Sul, Brazil, on the Paraná-Beni divide in E Bolivia, and on the headwaters of Río Bermejo in Salta, Argentina. — Map 39. — Fl. X-II.
Local Names and Uses - Guaiacán bianco, palo barroso (Argentina, both used for other species); arapiraca (Bahia); triadim.
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Discussion
In South America south of the Equator there are two species of Chloroleucon deceptively similar in finely divided microphyllidious foliage: Ch. foliosum and Ch. acacioides. The former has a relatively broad, toughly coriaceous pod 13-24 mm wide, either falcate or recurved into an open ring, the latter a thinly leathery pod only 6-7 mm wide, tightly coiled into a compressed spiral. As shown on Map 39, their ranges are vicariant, but on the whole well separated. One fruiting specimen from the Paraguay basin in Bahia (Machado Portela, J. N. Rose 19964 [NY, US], which we have referred to Ch. foliolosum because of the falcate lignescent fruit, has atypical foliage, with leaf-formula iii-v/17-20 and leaflets to 7 x 1.8 mm, suggesting passage to Ch. dumosum. Since Ch. foliolosum and Ch. dumosum are sympatric in this region the possibility of hybridization cannot be dismissed.
We have found no significant difference between Bahian Ch. foliolosum and the populations distantly disjunct in Mato Grosso and northern Argentina that have been described as Pithecellobium myriophyllum and P. grisebachianum. A similar discontinuous dispersal is known in Mimosa hexandra M. Micheli (Barneby, 1991: map 16).
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Common Names
Guaiacán bianco, Palo barroso., Arapiraca, triadim
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Distribution
Ceará Brazil South America| Pernambuco Brazil South America| Bahia Brazil South America| Piauí Brazil South America| Mato Grosso do Sul Brazil South America| Bolivia South America| Salta Argentina South America|