A New Species of Zinowiewia (Celastraceae), and Notes on the Genus in Ecuador

Abstract

Zinowiewia is a small neotropical genus of 17 species. Two species are reported to occur in Ecuador: Zinowiewia australis Lundell and the new Zinowiewia madsenii C. Ulloa & P. M. J0rgensen. A key to the Ecuadorian species, descriptions, and an illustration of the new species are provided. Turczaninow (1858) described Wimmeria integerrima, questioning its generic position. A year later he recognized this species as belonging to a new distinct neotropical genus, Zinowiewia Turczaninow (Turczaninow, 1859). The genus remained monotypic until Lundell (1938) described six new species. The following year he published a revision of the genus containing seven species (Lundell, 1939a), and shortly after he added two new species (Lundell, 1939b, 1940). Between 1964 and 1988 five species from Mexico and Central America were described (Lundell, 1981, 1985, 1987; Williams, 1964) and two from northern South America (Lundell, 1970; Steyermark, 1988), bringing the number of recognized species to 16. The genus was recently reported to occur in Ecuador from collections made in the province of Loja (Madsen, 1991; Ulloa Ulloa & J0rgensen, 1993). These collections appeared to represent an undescribed species endemic to a small area of the Podocarpus National Park. Further examination of the specimens deposited at the Missouri Botanical Garden showed the presence of a second species in Ecuador, Zinowiewia australis Lundell. The species of Zinowiewia are trees or shrubs characterized by their one-winged samaras, decussate leaves, and oneto several-times forked cymes. The genus is distributed from south-central Mexico through Central America to Peru, from 250 to 3,150 m elevation. At present two distinct species occur in Ecuador. KEY TO THE SPECIES OF ZINOW1EWIA IN ECUADOR la. Leaves 4.2-9 cm long, 2-4.5 cm wide, rembranaceous to subchartaceous, petioles 6-11 mm long; cymes subsessile, 4to 6-times for-ked; samaras 20-28 mm long, 7.5-17 mm wide; Amazonian lowlands ...... Zinowiewia australis lb. Leaves (0.9-)1.8-3(-4.2) cm long, (0.7-)1.41.8(-2.3) cm wide, subcoriaceous to coriaceous, petioles 2-4 mm long; cymes on peduncles up to 8 mm long, 1to 2-times forked; samaras 14-19 mm long, 4-7.5 mm wide; upper Andean forest ........ Zinowiewia madsenii Zinowiewia australis Lundell, Bull. Torrey Bot. Club 65: 469. 1938. Tree to 40 m high; buttressed; trunk canaliculate; bark fissurate (Palacios et al. 3528); branchlets slender. Leaves membranaceous to subchartaceous, dark green; petioles deeply canaliculate, 6-11 mm long; leaf blades ovate-elliptic, lanceolate or elliptic, 4.2-9 cm long, 2-4.5 cm wide, apex acuminate to apiculate, base narrowed, acute, decurrent, margin revolute; venation reticulate, midvein impressed above, prominent beneath, the main lateral veins 4-6 on each side, elevated above and beneath. Inflorescence a dense cyme on mostly defoliate branches, to 2.4 cm long, forked 4-6 times, subsessile, peduncle up to 1.5 mm long, primary branches up to 7 mm long; bracts and bracteoles up to 0.8 mm long; pedicels of all flowers jointed at or near the base, up to 0.5 mm long below joint. Flowers green; calyx lobes 5, 0.3-0.5 mm long, 0.7-0.8 mm wide, widely ovate, slightly 3-lobed, central lobe acute, margin light green, entire; petals 5, 0.9-1.2 mm long, 0.5-0.8 mm wide, lanceolateovate, acute to obtuse; stamens 5, filaments 0.6 mm long, borne on angles of disk, anthers 0.2 mm long; disk fleshy, pentagonal, margin slightly elevated; ovary 2-locular, submerged in the disk, 2 ovules in each locule. Fruits (from the original description and Peruvian material) broadly oblanceolate to obovate samaras, 20-28 mm long, 7.5-17 mm wide, strongly veined, apex rounded, mucronate; seed 1, 8-11 mm long, 2.5-3 mm diam. Distribution. Venezuela to Peru, in lowland to submontane forests, 250-1,250 m elevation. Zinowiewia australis is characterized by its large, dark, thin leaves, long peduncles, subsessile cymes forked 4-6 times, and large obovate samaras. NOVON 4: 183-186. 1994. This content downloaded from 157.55.39.11 on Sun, 17 Apr 2016 06:11:44 UTC All use subject to http://about.jstor.org/terms