A New Species of Gonolobus (Apocynaceae, Asclepiadoideae) from Mesoamerica W D. Stevens and Olga Martha Montiel Missouri Botanical Garden, P.O. Box 299, St. Louis, Missouri 63166-0299, U.S.A. [email protected]; [email protected] RACT. Gonolobus taylorianus, a Mesoameri-can endemic, is described and illustrated. Key words: Apocynaceae, Asclepiadoideae.Gonolobus, Mesoamerica. The genus Gonolobus Michaux has about 150species ranging from temperate North America totemperate South America. The greatest diversity isfound in southern Mexico and northern CentralAmerica. The genus is most clearly distinguishedfrom the other genera of the Gonolobinae by anextra anther appendage that is always found on thedistal dorsal edge of the anther and is usuallyfleshy, of a contrasting color, and more or less pat-ent. Additionally, the corona is always a simple,entire or 5-lobed, fleshy ring at the junction of thecorolla and the gynostegium, there is frequently awell-developed corolline annulus, the corolla lobesare frequently strongly overlapping and twisted inbud, the indumentum is usually comprised of hairsof one length, and the follicles usually have fivecomplete wings. This new species came to light in the process of preparing floristic accounts for Flora de Nicaragua and Flora Mesoamericana, and is here described. Gonolobus taylorianus W. I). Stevens & Montiel. sp. nov. TYPE: Nicaragua. Matagalpa: along road from Muv Muy to Esquipulas. ca. 19 km W of Esquipulas, 12�42'N, 85�45'W, elev. 400 m, 30 July 1978, W I). Stevens 9563 (holotype. MO). Figure 1. Gonolohlnu tavlorianus W. . . Stevens & Montiel; ex af-finitate (G. nigri et specierum aflinium floribus majoribus et indumento annuli limbique eodem distinguen(lus. Vine, twining (to right), woody below, corky bark absent; latex white, roots fibrous; young stems pu-bescent at nodes and in 2 lines on internodes, in-dumentum mixed, long hairs multicellular, pale yellow, reflexed, 0.15-0.4 mm long, short hairs multicellular, capitate-glandular, pale brown, erect, 0.05-0).1 mm long; internodes 2-16 cm long. Leaves opposite, without pseudostipules. blades ovate to elliptic. 5.9-12.5 X 2.2-7. 1 cm, apex acu-minate to attenuate, base lobate, lobes divergent toconvergent, sinus 0.3-1.7 cnm deep, glabrous orwith scattered long (0.3-0.7 mm) and/or glandularhairs, lateral veins pinnate, 4 to 6 pairs, middleveins 35-45� to midrib, colleters 2 or 4; petiole2.2-7 cm long, glabrous or with mixed indumentumon adaxial side. Inflorescence extra-axillary. I pernodle. congested-racemiform, 4-to 18-flowered.with indumentum of stem or rarely glabrous, sessileor peduncle 1-6(-13) mm long, axis 1-10 mm long,pedicel 4-11 mm long, bracts 0.6-2.6 X 0.1-0.5mm, linear: calyx tube 0.5-1.2 mm long, with 1 to2 colleters per sinus, lobes lanceolate to deltate,with acute tips, reflexed. 2.3-6.2 X 1.3-2 nm.green, glabrous or with a few long hairs on marginand base o-abaxial side; corolla rotate, aestivationimbricate and dextrorse, brown, green, or purple,tube 1.7-2.7 mm long, glabrous or with mixed in-dumentum outside, long hairs to 0.1 mm long, in-side densely pubescent with glassy, erect or curly,unicellular hairs 0.1-0.3 mm long, faucal annulustubular. 5-lobed, 0.5-1.1 mm tall at lobes. 0.3-0.6mm tall between lobes, outside with same indu-mentun as adjacent corolla tube, corolla lobes del-tate to lanceolate with acute tips, with conspicuousto inconspi: uous auricles at base, 6.6-11.7 X 3.2-4.7 amm. re lexed, glabrous or with mixed indumen-tum outside, inside glabrous to densely pubescentwith glassy. erect or curly. unicellular hairs 0.1-0.3mm long: gynostegium with stipe 0.3-0.6 X 0.7-1rum. 5-ribbed, corona � hidden by faucal annulus,a 5-lobed disk, adnate to corolla and gynostegiumstipe, 0.3-0.6 mm thick, 0.6-1.2 mm wide betweenlobes, 0.9-1.5 mm wide at lobes, yellow, antheraplpendrages deflexed to nearly patent, spathulate.0.8-1.3 nun long, 0.9-1.3 mm wide at tip, fleshy,smootl to papillate, orange, terminal appendagestightly appressed to margin of style apex, 0.2-0.5X 1.7-2.1 mm, green, guide rails straight, parallel.0.6-1.2 X 0.1-0.3 mm; corpusculum 0.2-0.28 X0.07-0.13 mm, sagittate, pale brown to black,translators 0.25-0.33 X 0.1-0.18 mm. broadlywinged, p llinia 0.8-1.03 X 0.37-0.53 mm, ob-ovate to p yriform, somewhat asymmetrical, exca-NOVON 12: 551-554. 2002.