Zygia transamazonica Barneby & J.W.Grimes
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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. Amazonas, mun. de Novo Aripuanã: Rod. Transamazônica a 400 km de Humaitá, Projeto INCRA-Río Juma, vicinal Corujá a 30 km da Transamazônica, 7°15'S, 60°W, 3.V. 1985, C. A. Cid Ferreira 5997. — Holotypus, INPA n.v.; isotypus, NY.
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Description
Species Description - Unarmed macrophyllidious trees 10 m with trunk 1.5 dm dbh, resembling Z. ramiflora in aspect and lf-formula but the lf-axes glabrous, the almost glabrous cauliflorous inflorescence composed of few-fld capitula, the lf-nectaries wanting, and the flowers pink, the rudimentary puberulence of inflorescence- axis and bracts golden-brown. Stipules not seen; no terminal resting bud. Lf-formula iii/6; lf-stks 7-8 cm, the petiole including pulvinus ±2.5 cm, at middle ±2 mm diam, the interpinnal segments 2.5-3 cm, the shallow ventral sulcus continuous between pinna- pairs; pinnae distally accrescent, the rachises of furthest pair 8-9.5 cm, the longer interfoliolar segments 1.5-2 cm, the ventral groove bridged at insertion of lfts; lft-pulvinules 0.7-0.9 x 0.9-1.2 mm, the blade sessile against rachis; lfts decrescent proximally, thence subequilong, the blades elliptic-acuminate from postically blunt-auriculate, antically half-cuneate base, at very apex obtuse apiculate, those of further pairs 5-6.5 x 1.6-2.3 cm, 2.6-3.7 times as long as wide; venation pinnate, the subcentric, almost straight midrib sharply prominulous on both faces, the ±10—14 major and random intercalary secondary nerves widely ascending to anastomosis well within the plane margin and finely prominulous on both faces, a tertiary reticulum of veinlets well defined only dorsally. Pseudoracemes of capitula clustered on brachyblasts along annotinous and older branches, the primary axis <1 cm, the peduncles solitary, subtended by a deltate bract <1 mm, the longer peduncles 3-5 mm; capitula 7—11-fld, the subglobose receptacle 1-1.5 mm; floral bracts 0.7-0.9 mm, persistent; fls homomorphic, sessile, glabrous; calyx ovoid-campanulate 1.4-2 x 1-1.3 mm. the deltate teeth ±0.3 mm; corolla narrowly trumpet-shaped ±6.5 mm, the erect ovate lobes ±1 mm, the tube only faintly veined; androecium 30-merous, 26 mm, the slenderly cylindric tube 7 mm, the stemonozone ±0.4 mm; a shallowly lobed disc 0.3-0.45 mm tall surrounding the sessile ovary, this slenderly ellipsoid, at anthesis glabrous; style filiform, not dilated at apex. Pods unknown.
Distribution and Ecology - In terra firme forest on clay substrate, known only from the type-locality at 7°15'S, 60°W, on middle Río Aripuanã in SE state of Amazonas, Brazil. — Not mapped. — Fl. V-VI(-?). — "Madeira dura, cas- tanha, com cerne e alburno indistinto; flores vistosas de cor roseas."
Relationships - Zygia transamazonica closely resembles Z. ramiflora in aspect and in number and form of leaflets but differs significantly in the well developed petioles, glabrous leaf-axes devoid of nectary, and capitulate rather than spicate units of inflorescence. The quite glabrous calyx and relatively long androecium that are mentioned in the Latin diagnosis are probably less reliable, perhaps only individual, differences. A pink perianth distinguishes the typus of Z. transamazonica from all of Z. ramiflora except the somewhat ambiguous element described as Pithecellobium dinizii, in which the pinnae are only 1 or 2 pairs per leaf.
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Distribution
Amazonas Brazil South America|