Zygia brenesii (Standl.) L.Rico
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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, collected 1 Mar 1922, F!; isotypus, NY!.
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Synonyms
Pithecellobium palmanum Standl.
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Description
Species Description - Arborescent shrubs with the gray bark, ample lfts, and cauliflory of sect. Zygia, reportedly attaining 15 m but seen in fl when 3 m tall, glabrous except for brownish-puberulent young lf- and inflorescence- axes, the papery lfts bicolored, dull brown-olivaceous above, paler beneath, the loosely racemose or subumbellate, relatively long red fls borne either on the main trunks, or on slender annotinous branchlets, or on both. Stipules lanceolate 2-6.5 mm, 3-5-nerved when young, early papery and deciduous. Lf-formula i/(21/2-)31/2-41/2, each pinna (5-)7-9-foliolate; petioles stout ±3-6 x 2-3 mm; nectary at top of petiole cupular 1-1.7 mm diam, sometimes incipiently stipitate; rachis of pinnae 5.5-18 cm, the longer interfoliolar segments 2-5 cm; lft-petiolules ±2-3.5 mm; lfts irregularly accrescent distally, the blades inequilaterally elliptic, lance-elliptic, or (ob)ovate-elliptic from asymmetrically cuneate base, short-acuminate, the distal pair in ampler lvs 7-19 x 2.6-7 (in some smaller sun-leaves only 5.5 x 2.5) cm, (2-)2.2-3.4 times as long as wide; venation subsymmetrically pinnate, the midrib either straight or gently incurved, the secondary nerves ±5-8 on each side, the tertiary and reticular veinlets weakly raised on both faces. Racemes ±9-15-fld, the simple axis, including short peduncle, 6-35 mm; bracts <1 mm, persistent; pedicels at and after anthesis (1.2-)1.6-4(-5.5) x 0.4—0.6 mm, sometimes scarcely perceptible in bud; perianth (4—)5-merous, red, glabrous except for sometimes micropuberulent corolla-lobes, the membranous calyx faintly 5-nerved, the corolla weakly striate in age; calyx campanulate or deeply campanulate (1.8-)2-4 x 1.6-2 mm, the depressed-deltate or subobsolete teeth 0.10.4 mm; corolla cylindric a trifle dilated upward, (16.5-) 18-21 mm, the narrowly lance-ovate lobes 2.3-4 mm, not over half as long as corolla; androecium 52-56-merous, the stemonozone 1.2—3(—5) mm; intrastaminal nectary 0.6-1 mm; ovary at anthesis glabrous. Pods not seen. The diagnostic syndrome of Z. brenesii consists of: shortly racemose fls; relatively long, red corolla; and pluristaminate androecium with proportionately short tube and red tassel.
Distribution and Ecology - In wet forest or forest remnants, commonly along streams, 800-1050 m, apparently confined to the environs of San Ramón, in prov. Alajuela, Costa Rica. — Not mapped. — Fl. II-V.
Relationships - Zygia brenesii and Z. palmana are here regarded as conspecific. Standley described Pithecolobium brenesii as similar to Nicaraguan P. englesingii but larger-flowered; he offered no diagnostic remark about P. brenesii. Rico transferred both to Zygia, but with characteristic insouciance vouchsafed no supporting evidence. It seems implausible that two narrowly sympatric and endemic species that share a flower unusual elsewhere in their genus could coexist in Alajuela; but proof is contingent on study of the fruits.
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Distribution
Alajuela Costa Rica Central America|