Taxonomic Notes on Mesoamerican Annona Section Atta (Annonaceae), including Annona pruinosa sp. nov.

Abstract

A new species of Annona sect. Atta from the upper altitudinal limit of the Pacific dry forest of Nicaragua and Costa Rica is proposed based upon a distinctive abaxial leaf epidermis. In addition, the analysis of flowers discovered for Annona longipes necessitates its transfer to section Atta. During preparation of treatments of the Annonaceae for the Flora de Nicaragua and the Manual to the Plants of Costa Rica, a new species of Annona L. sect. Atta C. Martius has been identified based on material from Nicaragua and Costa Rica. In addition, recent flowering collections of Annona longipes Saff. from Veracruz, Mexico, reveal its incorrect placement by Safford (1913) in section Pilannona Saff., and indicate its proper placement in section Atta. Annona (section Atta C. Martius) pruinosa Schatz, sp. nov. TYPE: Nicaragua. Carazo: Finca de Minco Cabrales, 700 m al sur del reloj, 18 June 1982 (fl, fr), L. Reyes V. 64 (holotype, MO; isotype, HNMN). Figure 1. A speciebus aliis Annonae sectionis Attae laminis subtus pruinosis differt. Tree to 10 m tall; young branches very sparsely white-tomentose, at length glabrescent. Petiole 0.81.3 cm long, slender, deeply canaliculate, very sparsely tomentose, drying black; lamina chartaceous, elliptic to obovate-elliptic, 6.4-15 cm long, 3.2-8.3 cm broad, the base cuneate to obtuse, the apex acute to rounded, the upper surface glabrous, the lower surface granular pruinose and initially sparsely white-puberulous, at length glabrescent, the venation eucamptodromous with 9-14 secondary veins per side, the primary vein slightly impressed adaxially, prominently elevated and sparsely golden puberulous, as are the slender secondary veins, abaxially. Flowers solitary, terminal but appearing leaf-opposed or supra-axillary by displacement during growth of the renewal shoot; pedicel slender, 1.3-2.4 cm long, to 3.1 cm long, 0.2 cm diam. and becoming rigid in fruit, white-tomentose, bearing a minute bract 0.8-0.9 cm from the base; sepals triangular, 0.2-0.3 cm long, 0.3 cm broad, the apex acute, densely white-tomentose; petals 3 (the outer petal whorl only, the inner whorl absent or at most represented by tiny vestigial petals), fleshy, triquerous, narrowly oblong-elliptic, 1.8-2.4 cm long, 0.5-0.8 cm broad, the apex acute to obtuse, the base concave inside, the outer surface white-sericeous toward the base, becoming sparsely puberulous toward the apex, the inner surface densely tomentose; stamens numerous, 1 mm long, the connective expanded truncate discoid, minutely papillose, yellow, contrasting with the white thecae; carpels 25-36. Fruit syncarpous, subglobose to broadly ovoid, to 4.5 cm long, to 4.5 cm diam., the apex rounded, the surface initially areolate, but then smooth with no evidence of the individual carpels at maturity, green, or light and dark green mottled, initially puberulous, at length glabrescent; seeds flattened ellipsoid-obovoid, to 1.6 cm long, 0.9 cm broad, 0.6 cm thick, the seed coat very thin, smoothreticulate, light brown. Paratypes. COSTA RICA. GUANACASTE: Parque Rinc6n de la Vieja, Hacienda Santa Maria, sendero a las pailas, 10?48'N, 85010'W, 700-800 m, 13 Aug. 1987 (fr), G. Herrera 693 (CR, MO); El Mirador, Rio Negro, 10047'40N, 85018'35W, 1 Oct. 1990 (fr), G. Rivera 679 (CR, MO). PUNTARENAS: San Luis, Monteverde, Rio Guacimal, 10016'N, 84?49'W, 700 m, 24 June 1988 (fr), Bello et al. 24 (CR, MO, U), Cant6n de Puntarenas, Monteverde, cliff edge on Pacific slope, Bajo Tigre trail, 10018'N, 84048'W, 900 m, 20 Oct. 1990 (fr), Haber & Zuchowski 10110(CR, MO), 27 Dec. 1991 (fr), Schatz et al. 3230 (MO). NICARAGUA. CHONTALES: ca. 2.8 km above (N of) Cuapa, ca. 12017'N, 85023'W, 400-500 m, 4 Sep. 1977 (fr), Stevens 3634 (HNMN, MO, WIS); 2-3 km NE of Cuapa, 12?17'N, 85?22'W, 400 m, 24 Sep. 1983 (fr), Nee & Sebastian 28486 (HNMN, MO, WIS). BOACO: Las Pitas, carretera a Camoapa (No. 19), 12?28'N, 85?35'W, ca. 400 m, 29 Aug. 1981 (fr), Moreno 10651 (HNMN, MO). Distribution and habitat. Annona pruinosa is known from southern Nicaragua and the Pacific slope of the Tilaran range in northwestern Costa Rica, in moist forest between 400 and 800 m, i.e., the upper altitudinal limit of the Pacific dry forest. The affinities of Annona pruinosa within section Atta lie probably with several Caribbean species (A. urbaniana R. E. Fries, from Haiti; A. praetermissa Fawcett & Rendle, from Jamaica; and A. cubensis NOVON 2: 249-251. 1992. This content downloaded from 157.55.39.124 on Fri, 13 Jan 2017 18:13:08 UTC All use subject to http://about.jstor.org/terms