Zygia unifoliolata (Benth.) Pittier (Zygia unifoliolata (Bentham) Pittier)
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Authors
Rupert C. Barneby
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Authority
Barneby, Rupert C. & Grimes, James W. 1997. Silk tree, guanacaste, monkey's earring: A generic system for the synandrous Mimosaceae of the Americas. Part II.
, , and . Mem. New York Bot. Gard. 74: 1-149. -
Family
Mimosaceae
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Scientific Name
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Type
"Brazil, [L. Riedel] commun. Langsdorff." - Holotypus, labeled "Inga 2, Rio Madeira, Riedel ex herb. Mus. Petrop., K (hb. Bentham.)! = NY Neg. 2024.
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Synonyms
Feuilleea unifoliolata (Benth.) Kuntze, Pithecellobium unifoliolatum Benth.
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Description
Species Description - Macrophyllidious cauliflorous shrubs and slender treelets 2-8 m, with pallid annotinous and older branches, either glabrous throughout or the new branchlets and the lf- and inflorescence-axes minutely puberulent, the chartaceous lfts dull olivaceous, paler beneath, the few-fld capitula of usually fragrant, whitish or pinkish fls nearly always fasciculate at defoliate nodes but exceptionally pseudoracemose on an incipient primary axis <1 cm. Stipules fugacious or perhaps in some plants lacking, those subtending new lvs deltate-triangular 0.3-0.4 mm, faintly 1-nerved. Lf-formula 1/½, each lf bifoliolate; petiole 1.5-6(-10) x 0.9-2.3(-2.6) mm, charged at tip with a sessile, round, almost plane and button-shaped or shallowly cupular thick-rimmed nectary 0.7-1.9 (-2.5) mm diam, a similar but smaller nectary sometimes at tip of each pinna-rachis but this often lacking; pinna-rachises (1 —) 1.5—5 (—6) mm; pulvinule of lfts 0.8-3.5 mm; lft-blades narrowly or broadly elliptic, ovate-elliptic or linear-elliptic from inequilaterally cuneate base, usually shortly or obscurely, exceptionally attenuately acuminate, the larger ones 6-16 (-19.5) x 2.5-7(-8) cm, or in SW Venezuela (Aymard 9078, NY) 20-27 x 7-8 cm, 1.8-3.8(-4.6) times as long as wide; venation pinnate, the subcentric, straight or slightly incurved midrib giving rise on each side to 6-12 major incurved-ascending (and indefinite intercalary) secondary nerves brochidodrome well within the plane margin, these and tertiary venulation and sometimes a reticulum of veinlets scarcely or not raised on upper face, more sharply defined beneath. Peduncles very slender 1.5—10(—13) mm; capitula 5-16-fld, the receptacle usually globose or plumply ellipsoid 0.7-2 mm, exceptionally to 4 mm long; bracts ovate acute 0.3-0.6 mm, persistent; perianth glabrous except for microscopically ciliolate orifice of and rarely apically puberulent corolla, the corolla tube ±15-striate, the lobes nerveless; calyx cupular-patelliform 0.25-0.6 x 0.6-0.8 mm or rarely more deeply campanulate ±1x1 mm, the teeth always minute; corolla ochroleucous or pinkish- to yellowish-green, subtubular or distally dilate 5.3-7.3 mm, the erect ovate lobes 0.6-1.3 mm; androecium 20-36-merous, 17.5-24 mm, the tube (7-)9-13.5 mm, exserted (1—)2.5—7.5 mm, the tassel white or ochroleucous; intrastaminal disc 0.2-0.45 mm, sometimes obsolescent; ovary 1.2-1.8 mm, contracted at base into a stipe as long as the disc and rather abruptly at apex into the style, glabrous; stigma poriform ±0.15 mm diam. Pods solitary, sessile or almost so, in profile broad-linear retrofalcate or annular and often randomly twisted, when well fertilized 9-19.5 x 1.4-2.8 cm, planocompressed becoming low convex over each seed, the coriaceous, green but brunnescent, glabrous valves framed by scarcely or undulately constricted sutural keels 1 mm wide or less; dehiscence of the genus; seeds (scarcely known) transverse, plumply disciform 13-? mm diam.
Distribution and Ecology - On riverbanks, in gallery woodland, and in forest subject to annual flooding, locally gregarious from sea level to 240 m, scattered over the Orinoco and Amazon basins between 9°N and 10°S latitude in Venezuela (Apure to Anzoátegui), E Colombia (W to Sa. de la Macarena), NE Peru (Loreto), Brazil (Amazonas to centr. Pará) and extreme NE Bolivia (Pando); seemingly isolated in centr. Panama and lowland Caribbean Costa Rica, and once recorded from N Chiapas, Mexico (mun. Ocosingo, Martínez 10932, NY). — Map 38. — Fl. throughout the year, most prolifically in X—II.
Variation - Like Z. latifolia, this species varies greatly in size of leaflets and width of pods, but we find no consistent geographic segregation. An extreme form from state of Amazonas, Venezuela (Aymard 9078, NY), is remarkable for acuminately caudate leaflets attaining 20-27 x 7—8 cm and for pods to 2.8 cm wide, not matched elsewhere in the species. This variant was seen by the collector as a vine, rather than a bushy shrub, and may perhaps turn out, when the flowers are known, to deserve some taxonomic status.
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Common Names
Yacushimbillo , Guamita
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Distribution
Apure Venezuela South America| Anzoátegui Venezuela South America| Colombia South America| Loreto Peru South America| Amazonas Brazil South America| Pará Brazil South America| Pando Bolivia South America| Panama Central America| Costa Rica South America| Chiapas Mexico North America|