Arbustos o árboles pequeños, siempreverdes o deciduos. Hojas opuestas o raramente verticiladas, simples, enteras, dentadas o lobadas, estípulas ausentes o diminutas. Inflorescencias cimas paniculado-compuestas, umbeliformes, pedunculadas, bracteadas, flores pequeñas; corolas 5-lobadas, rotáceas, campanuladas o tubulares, blancas; estambres 5; ovario de apariencia 1-locular, con un solo óvulo fértil, estilo corto y cónico, estigmas 3, capitados. Fruto una drupa con un solo pireno, algunas veces comprimido o sulcado.
Un género ampliamente distribuido con ca 120 especies, principalmente del este de Asia y este de Norteamérica, pero bien representado en México, Centroamérica y los Andes; 2 especies se conocen en Nicaragua. Muchas especies son cultivadas como ornamentales en las zonas templadas.
C. Morton. The Mexican and Central American species of Viburnum. Contr. U.S. Natl. Herb. 26: 339366. 1933; M. Donoghue. Systematic Studies in the Genus Viburnum. Ph.D. Thesis, Harvard University, Cambridge. 1981.
Shrubs or small trees, deciduous or sometimes evergreen. Branchlets glabrous or pubescent with simple, fascicled or stellate hairs, rarely lepidote hairs; winter buds perulate or naked. Leaves usually opposite, rarely ternate, simple, petiolate, entire, dentate, or 3-5-lobed; stipules usually small or absent. Inflorescence terminal or at apices of short branches with 1- or 2-jugate leaves, compound, corymbose- or paniculate-cymose. Flowers small, actinomorphic, but sometimes marginal flowers of inflorescence enlarged, somewhat zygomorphic and sterile, rarely entire inflorescence consisting of such sterile flowers; bracts and bracteoles usually small and caducous. Calyx small, 5-toothed. Corolla white, rarely reddish, pinkish, or greenish, rotate, campanulate, hypocrateriform, or tubular, 5-lobed. Stamens 5; filaments filiform; anthers medifixed, longitudinally dehiscent, introrse. Ovary semi-inferior, 3-loculed, 1 locule fertile with a single ovule, and 2 sterile; styles short; stigmas slightly capitate to 3-lobed. Fruit a 1-seeded drupe with a ± compressed pyrene, red, purplish, black, or rarely yellow when mature.
Shrubs or trees, sometimes scandent; branches solid or with soft pith, the twigs terete, often pubescent. Leaves deciduous or evergreen, in some species with bud 6A list of generic synonyms is provided by Hutchison, Genera of Flowering Plants 2: 85. 1967. Only the above names have been used for Panamian material. This content downloaded from 126.96.36.199 on Thu, 9 May 2013 15:30:06 PMAll use subject to JSTOR Terms and Conditions164 ANNALS OF THE MISSOURI BOTANICAL GARDEN [VOL. 60 scales, opposite or ternate, simple, not connate, the margins entire or dentate, the teeth often callose-glandular, mostly pubescent with simple, stellate, or lepidote hairs and often with reddish-drying glands, often penninerved; petiolate, the petioles often glandular, appendaged, and clasping; stipules mostly inconspicuous or wanting. Inflorescences axillary or terminal, compound cymes or rarely pani- cles, bracts and bracteoles mostly present, sometimes sub-foliaceous, the pedicels or peduncles often articulating at the base. Flowers white or rose, fragrant, bisexual and regular or the outer flowers of the inflorescence sometimes neuter and irregular; calyx tube ellipsoidal or cylindrical, pubescent, glandular or glabrous, adnate to the ovary, the lobes mostly persistent, equalling the tube or shorter; corolla perigynous, mostly campanulate, sometimes rotate or tubular deeply 4-5-lobed, the lobes quincuncial (? or imbricate) in bud; stamens equal, the filaments inserted at the base of the corolla tube, straight and sometimes compressed or variously thickened along their length, the anthers exserted, dor- sifixed and versatile, ellipsoidal, opening introrsely; ovary immersed halfway or more in the perianth tube, 3-1-locular, the locules not radially symmetrical with respect to the floral axis, the ovules 1 per locule, pedulous from the apex of the locule, anatropous, the superior portion (style) glabrous, glandular, or pubescent, persistent on the fruit, the stigmas 3, free or more or less connate, rarely appen- daged; disc absent. Fruit a baccate drupe, sometimes brightly colored, globose, ellipsoidal, ovoid, or sometimes compressed, 1-seeded (by abortion); the seeds oblong, compressed, grooved, or the margins inflexed, the raphe lateral, the endosperm fleshy and rarely ruminate, the embryo minute, straight, situated at the apex of the seed, the cotyledons semi-terete.
Shrub or tree to 8 m tall; branches terete, mostly glabrous and grey or reddish, dark, sometimes drying almost black, the twigs 6-2& cm long, densely tomentose with mostly sessile multangulate stellate hairs; bud scales tomentose but glabres- cent. Leaves ovate, apically obtuse or acuminate, basally subcordate, rounded, or obtuse, often oblique, the margins entire or toothed, the teeth often appearing gland-tipped, above with dispersed to dense, sessile or stalked multangulate hairs and sparse, small, short-stalked glands, sometimes glabrescent, beneath densely tomentose, the midvein mostly recurved, the secondary veins 4-5 on each side, obscure near the leaf apex; petioles 5-15 mm long, tomentose; stipules absent. Inflorescence terminal, 2-4-times compound cymes 5-8 cm in diameter, the bracts narrow, spatulate to lanceolate, variable in size, to 5 cm long, the bracteoles linear, 2-5 mm long, rarely equaling the flowers, mostly pubescent; pedicels 1-2 mm long, tomentose. Flowers white, fragrant; calyx 2 mm long, the tube cylindrical or obconical, mostly with numerous stalked, red-dying glands, seldom glabrous or with eglandular simple hairs, the lobes deltoid to obtuse, sometimes emarginate, conspicuously ciliate, rarely pubescent dorsally; corolla campanulate, glabrate with a few hairs inside and out near the apex of the tube, 2-3 mm long, lobed to ca. 1/2 way down, the lobes rounded, quincuncial in bud; stamens exserted, the filaments narrowed apically, slightly gibbous basally, the anthers ca. 1 mm long; the ovary 1-loculed, superior portion (style) conical, the stigmas 3, more or less distinct and unequal. Fruit an ellipsoid, black, juicy berry ca. 5 mm long.
A genus of about 100-200 species of wide distribution, numerous in the north temperate zone and on tropical mountains, rare in the Antilles, absent from New Zealand and Australia, and rare in eastern and southern South America. The Panamanian species are closely related and are restricted to the uplands of the Chiriqui Mountains.