Zygia collina (Sandwith) 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
Holotypus, K (2 sheets)! = NY Negs. 2034, 2035; isotypi, NY (2 sheets)!, U!, US!. — Marmaroxylon collinum (Sandwith) L. Rico, Kew Bull. 46: 516. 1991.
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Synonyms
Pithecellobium collinum Sandwith
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Description
Species Description - Amply multifoliolate trees 6-35 m with often crooked, when old narrowly buttressed trunk attaining 3 dm dbh, the new branchlets and all lf-axes puberulent with erect or forwardly incurved, yellowish hairs to 0.1-0.35 mm, the lfts glabrous, lustrous dark green (when dry brown) above, paler beneath, the inflorescence of short simple spikes of fragrant fls arising from knots on annotinous and older wood at points 2 m upward from the ground; axillary perules ovoid ±2 mm, puberulent. Stipules caducous (few seen), triangular or lanceolate 1.5-3 x 1-1.5 mm, externally nerveless. Lf-formula v-vii/12-18; lf-stks of longer lvs 7-13 cm, the petiole 0, the short deflexed amplexicaul first pair of pinnae inserted next to lf-pulvinus, the longer interpinnal segments 15-26 mm; petiolar nectary between first pair of pinnae sessile, shallowly cupular thick-rimmed or almost plane, 1.6-2 mm diam, similar but smaller and more deeply cupular ones between furthest 2-3 pairs of pinnae and yet smaller ones on pinna-rachis between 2-3 furthest pairs of lfts; pinnae distally accrescent, the penultimate pair often longest, the rachises of these 6-14.5 cm, the longer interfoliolar segments 5-10 mm; lft-pulvinules 0.2-0.3 x 0.5-0.9 mm, the blade sessile against rachis; lfts abruptly decrescent at base of rachis, thence subequilong or somewhat decrescent distally, the plane blades oblong or lance-oblong from obliquely truncate, obtusangulate base, gently incurved into a deltate, sharply mucronate tip, the longer ones (18-)20-27(-30) x 5-8(—11.5) mm, (2.6-)3-4.5 times as long as wide; venation palmate and pinnate, the slender subcentric midrib distally incurved, finely prominulous on both faces, the inner posterior primary nerve produced nearly to midblade, the outer 2-3 very short, the slender secondary nerves from midrib and open reticulum more sharply defined dorsally. Spikes subsessile, not subtended by a rudimentary lf, 7—15-fld, the rachis ±6-10 mm; bracts broadly ovate ±1 mm, persistent; fls sessile, the perianth minutely strigulose overall or glabrous except for lobes of calyx and corolla, the (4—)5-merous calyx deeply campanulate 1.7-3 x 1-1.4 mm, the depressed-deltate teeth 0.15-0.3 mm; corolla whitish subtubular, very slightly ampliate at the limb, 7-10 mm, the unequal ovate lobes ±1-1.2 mm; androecium 26-30-merous, 17-19 mm, the stemonozone ±1 mm, the tube 10 mm, the free filaments ochroleucous or (Fanshawe 1254) "pale crimson"; ovary in profile linear-elliptic 1.8-2 mm, contracted at base into a stipe 0.3 mm or less, conical at apex, at anthesis smooth glabrous; disc to 0.2 mm tall, sometimes obscure. Pods sinuously linear 7-10 cm, at each seed 8-10 mm wide, gently recurved or, after dehiscence, more or less contorted, the leathery valves framed by sutures 2-2.5 mm wide in dorsal view, densely brown-tomentellous overall, the cavity continuous, the endocarp smooth brown, erratically resin-speckled; dehiscence follicular, through the ventral suture, the valves explanate in age; seeds unknown.
Distribution and Ecology - In upland rain forest, 40-250 m, best known from NE Venezuelan Guayana (state of Bolívar and adj. T. F. Delta-Amacuro) and centr. Guyana (lower Essequibo valley), apparently disjunct on the headwaters of Río Orinoco near 63°46/W in state of Amazonas, and (sterile, needing confirmation) on Río Sipapo (Cerro Tigrito, ±67°W). — Map. 24. — Fl. II-V, VII. —Curarina; hueso or espina de pescado (Venezuela); uriridan (Arawak).
Relationships - Sandwith compared Z. collina with Pithecellobium umbriflorum, which is treated here as synonymous with Zygia ramiflora; except for leaf-formula the resemblance is close and almost certainly denotes a real relationship. So far as is known today, Z. collina is nearly uniform in leaf-architecture and inflorescence. The sympatric species of sect. Zygiopsis that resemble Z. collina in leaf-formula lack a nectarial disc in the flowers and are recognizable by the pale green coloring and sharply auriculate base of the leaflets.
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Common Names
uriridan
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Distribution
Bolivar Guyana South America| Delta Amacuro Venezuela South America| Amazonas Venezuela South America|