Zygia ocumarensis (Pittier) 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
"[VENEZUELA.] Aragua: Selvas inferiores del valle de Ocumare, Parque Nacional, 800 m.; flores Agosto 8, 1937. (Pittier 14099, tipo)." — Holotypus, VEN (2 sheets)!; isotypi, F 912944!, US 1692723!. — Marmaroxylon ocumarense (Pittier) L. Rico, Kew Bull. 46:
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Synonyms
Klugiodendron ocumarense Pittier, Marmaroxylon (Ocumarense) (Pittier) L.Rico, Marmaroxylon magdalenae L.Rico
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Description
Species Description - Macrophyllidious unarmed trees 5-15 m, sometimes branched from near base, with pallid gray annotinous branchlets and glabrous, olivaceous subconcolorous foliage, the lf-axes when young either glabrous or minutely puberulent and the small axillary pseudoracemose flowering branchlets together with capitula of small greenish or whitish capitula silky-puberulent with yellowish or brownish hairs to 0.1-0.2 mm. Stipules thick-textured deltate-triangular 1.3-3.5 mm, obscurely 3-5-nerved dorsally, persistent. Lf-formula ii/1; lf-stks subterete, the petiole including poorly differentiated pulvinus 2.5-7 cm, the petiole 6-24 mm, at middle 1.1-1.8 mm diam, the one interpinnal segment 2-5 cm; petiolar nectaries sessile, shallowly cupular thick-rimmed 1.2-2.5 mm diam between each pair of pinnae and slightly smaller, otherwise similar ones at tip of each pair of pinnae [2 basal nectaries described in protologue not seen in isotypes]; pinnae very unequal, the distal pair 1.5-2 times longer than the proximal, the rachis of distal pair (1.5—)2—4- cm; lft-pulvinules discolored, in dorsal view 2-3.5 x 0.6-1.6 mm; lfts ovate- or elliptic- acuminate from narrowly cuneate more or less inequilateral base, the acumen triangular ±1-1.4 cm, the whole blade 10-19.5 x 3.7-9.5 cm, 2.1-3 times as long as wide; venation primarily pinnate, the straight centric midrib giving rise on each side to ±7-10 major secondary nerves ascending and incurved to anastomosis shortly within the plane but sometimes subundulate margin and to many, more widely spreading minor ones, these all generating a reticulum of veinlets, the midrib and secondary veins pallid, scarcely raised above, sharply so beneath, the lesser veinlets only faintly prominulous. Pseudoracemes of capitula solitary or paired in the axil of coeval lvs, the primary axis usually 5-30 mm, sometimes subobsolete and reduced to 1-2 peduncles; peduncles either solitary or geminate 8-38 mm, either naked or charged near middle (rarely near apex) with a small stipuliform bracteole; capitula hemispherical 17-30-fld, the fls sessile homomorphic, the receptacle 2-3.5 mm; bracts triangular incurved 0.7-0.9 mm, persistent; perianth 5-merous, silky-pilosulous overall; calyx submembranous campanulate 2.3-3 x 1.1-1.5 mm, the deltate-triangular teeth 0.3-0.7 mm; corolla cylindric 7-9 x 0.6-0.7 mm, weakly 5-nerved, the lobes (unequal) ±0.4-1 mm, at apex hooded and dorsally gibbous, with incurved submembranous tip; androecium ±40- 66-merous, 12-18 mm, the slender tube 8-12 mm, exserted 1-2.5 mm; ovary at anthesis glabrous, subsessile, surrounded at base by a shallowly lobed disc 0.4-0.6 x 0.4-0.5 mm, the glabrous style filiform, a little shorter than the longer filaments. Pods solitary, subsessile, in profile undulately linear, falcately recurved through ±1/3-3/4 circle, compressed but turgid, 8-10-seeded, the sutures 2.5-3 mm wide, flattened dorsally but forming a low frame around the stiffly leathery, obscurely venulose valves, these shallowly depressed between seeds, densely minutely sordid- yellow-velutinous, the cavity not septate, the endocarp smooth, pale tan; dehiscence follicular, through the narrowly gaping seminiferous suture; seed-funicle linear compressed, twisted; seeds basipetal, attached just above base, plumply compressed-ellipsoid, in broad view ±13-15 x 0.6-0.7 cm, 4-5 mm thick, either nearly approximate along the cavity or contiguous and then obliquely truncate by mutual pressure, the dry brittle-papery ochre-brown testa loosely investing the blackish embryo, girdled by a darker nerve, and at middle of each broad face very thin and subtranslucent; pleurogram 0; no endosperm.
Distribution and Ecology - In semi-moist evergreen or drier semideciduous forest, 75-800 m, apparently local in the coastal cordillera of N Venezuela, in Miranda, Aragua, and Distrito Federal, and represented by a variety or close ally in N Colombia (see note following). — Not mapped. — Fl. II-IV, VIII, the full season not determined.
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Discussion
The foregoing description of Z. ocumarensis was prepared from five collections originating in the coast range of Venezuela. We have seen in addition two gatherings from the Magdalena valley in department of Santander, Colombia (O. Haught 2097, A, F, K, US 1742363, and Haught 1695, US 1707503) which are certainly congeneric and probably conspecific, though differing in some small points. Haught’s plants have only flowers; each was annotated by Killip as an undescribed species of Klugiodendron. The foliage of 2097 is indistinguishable from that of Venezuelan Z. ocumarensis, but that of no. 1695, a mere scrap of a twig with one leaf and one depauperate inflorescence, differs in leaf-formula of i/1 (not ii/1) and, as noted on the field label, "conspicuous purple stamens"; furthermore the perianth is nearly glabrous and strongly ribbed. The twig itself is infested with the fungus Sclerographium aterrimum Berkeley (det. C. Rogerson, NY), which could account for the anomalous features of the specimen, which we propose to leave aside as enigmatic. The abundantly flowering Haught 2097, of which the collector left no note as to color of the filaments, differs from the Venezuelan type in these particulars: stipules deciduous, though only tardily; lf-stks 9-10.5, the petiole 4.5-5.5 cm, the interpinnal segments 4—5 cm; lft-pulvinules 9-10.5 mm; larger lfts 13-18 x 6-7.5 cm, 2-2.8 times as long as wide; axis of pseudoracemes to 4.5 cm; peduncles 7-11 mm, some subtended by a rudimentary lf-stk with nectary; flowers very slightly heteromorphic, larger upward but without a modified terminal one; calyx 1.6-2.5 x 1-1.3 mm; corolla 4.8-6.5 mm; androecium 42-58-merous, 10-14 mm, the tube 6-8 mm; nectarial disc at base of ovary 0.5-0.8 mm tall. It has been segregated as Marmaroxylon magdalenae Rico, but whether its characters are racially significant we cannot foresee until the fruit becomes known. Search in the devastated forest of the Magdalena valley should be made for survivors.
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Distribution
Miranda Venezuela South America| Aragua Venezuela South America| Distrito Federal Venezuela South America|