Zygia brenesii

  • Title

    Zygia brenesii

  • Authors

    Rupert C. Barneby

  • Scientific Name

    Zygia brenesii (Standl.) L.Rico

  • Description

    39. Zygia brenesii  (Standley) L. Rico, Kew Bull. 46: 495. 1991. Pithecolobium brenesii Standley, Publ. Field Mus. Nat. Hist., Bot. Ser. 18 (Fl. Costa Rica): 506. 1937. — "[COSTA RICA. Prov. Alajuela:] entre Río Jesús y Alto de la Calera de San Ramón, 1000-1,050 meters, [Alberto M.] Brenes 5496." — Holotypus, collected 1 Mar 1922, F!; isotypus, NY!.

    Pithecolobium palmanum Standley, Publ. Field Mus. Nat. Hist., Bot. Ser. 18 (Fl. Costa Rica): 508. 1937. — "[Costa Rica. prov. Alajuela:] between San Miguel and La Palma de San Ramón, 1,000-1050 meters, [Alberto M.] Brenes 3496." — Holotypus, collected 20 May 1927, F!; isotypus, NY!. — Zygiapalmana (Standley) L. Rico, Kew Bull. 49: 504. 1991.

    Pithecellobium palmanum sensu Holdridge & Poveda, Arb. Costa Rica 1: 121 + fig. 1975.

    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.

    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.

    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.

    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.