Zygia heteroneura 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
ECUADOR. Pastaza: Río Curaray, alrededores de Laguna Garzayacu, 1°29'S, 76°39/W, 20-26 Aug 1985 (fl.), Walter Palacios (with D. Neill) 662. — Holotypus, NY.
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Synonyms
Zygia megistocarpa (Barbosa) E.Rico
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Description
Species Description - Slender macrophyllous cauliflorous trees 6-7 m, glabrous except for sordid-puberulent, spicate inflorescence, the lvs subsessile, the extremely ample, stiffly chartaceous lfts dull brownish-olivaceous when dry, a little paler beneath. Stipules and resting-buds not seen. Lf-formula i/2½, the lfts 10 per lf; petiole reduced to a stout wrinkled fuscous pulvinus 5-6 mm long and nearly as thick; petiolar nectaries not seen; rachis of each pinnae 16-26 cm (one of the pair a little shorter than the other), the interfoliolar segments 6 11 cm; lft pulvinules 6.5-11 x 2.5-3 mm, coarsely wrinkled; lfts ovate-elliptic from inequilaterally cuneate or cuneate-attenuate base, deltately acute, the larger ones ±25-32 x 9-12 cm; venation prominulous on each face of blade but more pronounced on lower one, the subcentric midrib giving rise on each side, in lower ¼ of blade, to 2 strong secondary nerves incurved-ascending long beyond midblade, the tertiary connecting venules subhorizontal-scalariform, generating a sinuous reticulum of veinlets. Axis of fl-spikes, including short peduncle, ±12 cm, the spreading sessile fls well separated along it; bracts deflexed, subulate <1 mm, deciduous; fl-buds pyri- form; perianth brownish-ochroleucous, puberulent with subappressed hairs 0.1-0.15 mm; calyx shallowly campanulate-patelliform, broader than long, ±0.7-1 x 2-2.2 mm, the depressed-deltate teeth at most 0.25 mm; corolla 5-6-merous, broadly trumpetshaped 7.5-8 mm, 4.5-5 mm diam at limb, the tube finely striate when dry, the lobes erect, ovate 2.3-3 mm, unequal; androecium not seen fully expanded, ±13-merous, the stemonozone 0.7-1 mm, the lobed intrastaminal disc 0.5-0.6 mm; ovary subsessile, slenderly compressed-ellipsoid, puberulent on lower half, glabrous distally. Pods unknown.
Distribution and Ecology - In understory of wet tropical forest, in moist alluvial soils, 230-250 m, known only from upper valleys of Ríos Napo and Curaray in provs. Napo and Pastaza, Ecuador, and on Río Corrientes just across the border in Loreto, Peru, within 0°55/-2°30/S, 76° 10'- 20'W. — Map 26. — Fl. VIII-IX.
Relationships - Zygia heteroneura has the long spikes of dull whitish flowers that are familiar in sympatric Z. coccinea var. oriunda but differs in greatly elongated leaflet-pulvinules, a characteristic venation, and twice as many stamens per flower. The venation of the leaflets recalls that of the leaf-blade of Abuta grandi- folia (Martius) Sandwith: two strong nerves arising from each side of the midrib close above its base and incurved-ascending nearly to the blade’s apex, suggesting in fact a quintuplinerved leaf-blade with scalariform tertiary venulation.
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Distribution
Napo Ecuador South America| Pastaza Ecuador South America| Loreto Peru South America|