New Species and Combinations in Costa Rican Orchids Robert L DressierMissouri Botanical Garden, P.O. Box 299, St. Louis, Missouri 63166-0299, U.S.A.; FloridaMuseum of Natural History; Marie Selby Botanical Gardens. Mailing address: 21305 NW 86th Avenue, Micanopy, Florida 32667, U.S.A.ABSTRACT. Four new species from Costa Rica aredescribed and illustrated: Oncidium imitans, Or-nithocephalus grex-anserinus, Paphinia subclausa,and Scaphyglottis atwoodii. The following new com-binations are made: Encyclia peraltensis (Ames)Dressier, Reichenbachanthus subulatus (Schlechter)Dressier, Stellilabium lankesteri (Ames) Dressier,amd Trichosalpinx rotundata (C. Schweinfurth)Dressier. As the orchid treatment for the Manual de la Flora de Costa Rica nears completion, several ad-ditional new species and combinations are needed. There remain a number of probable new species for which the available material is insufficient. Oncidium imitans Dressier, sp. nov. TYPE: Costa Rica. San Jos6: about 25 km N of San Isidro del General along the Interamerican Highway, 9�20'N, 83�41'W, 1800 m alt., tall wet ever-green forest on steep slopes, on roadside bank on moss-covered log, W. Burger & R. Baker 10075a (holotype, F). Figure 1. 0. obryzatoide similis sed bracteis longissimis tenuibus,sepalis lateralibus connatis, columna sine tabula infrastig-matica vel constrictione basali. Caespitose, pseudobulbs ovoid, compressed, ca.4 X 2 cm; leaves 1 apical, 2 sheathing, ligulate,narrowed basally, ca. 15 X 1.6 cm; inflorescenceca. 20 cm, simple, of 3-4 flowers; bracts long andnarrow, thin, scape bracts 4.5-5 X 0.4-0.5 cm, flo-ral bracts to 2.5 x 0.3-0.5 cm; sepals greenishyellow, callus white with red-brown spots, lip andpetals yellow, with red on margins of isthmus andred spots on column wings; dorsal sepal elliptic, 9X 2.5-3 mm, lateral sepals lance-elliptic, unitedfor ca. 7 mm, together 9 X 4 mm; petals oblong-oblanceolate, obtuse, 10 X 4 mm; lip 15 X 16 mm,base with a 2-mm-wide thickening to callus, laterallobes oblong, to 2.5 X 1.5 mm, isthmus subquad-rate, 5 X 4 mm, callus 2.5 X 4 mm, 7-lobed, mid-lobe 6 x 15-16 mm, shallowly retuse; column 8mm, trigonous-terete, without tabula infrastigmati-ca, wings ca. 1.5 x 3.5 mm.NOvoN 7: 120-126. 1997. I first encountered this species in the Jardfn Lan-kester, where a plant from Santa Marfa de Dota was labeled as 0. obryzatoides Kraenzlin. My wife and I photographed the flowers and preserved a couple in liquid, without questioning the identification. When I later studied 0. obryzatoides, it was im-mediately obvious that the plant from Santa Marfa de Dota was distinct. The long bracts, the column without a tabula infrastigmatica, and the partially united lateral sepals all suggest 0. warscewiczii Reichenbach f. Oncidium imitans may prove to be a natural hybrid of 0. warscewiczii. It has been col-lected it two localities, in each case identified as 0. obryzatoides. Though superficially similar to O. obryzatoides, the column without either tabula in-frastigmatica or basal constriction and the connate lateral sepals at once distinguish 0. imitans. The epithet, imitans, refers to its superficial similarity to 0. obryzatoides. Ornithocephalus grex-anserinus Dressier & Mora-Retana, sp. nov. TYPE: Costa Rica. Al-ajuela: dist. Sarapiquf, alrededores de Laguna Marfa Aguilar, elev. 500-700 m, 10�18'N, 84�11'0, 5 mayo 1992, D. E. Mora-Retana, F Pupulin & A. Herrera s.n. (holotype, USJ 49975). Figure 2. Habitu genere, sepalis ovatis carinatis apiculatis, pe-talis cuneato-unguiculatis spathulato-flabellatis. labellopandurato-oblongo callo humili. Plant psygmoid, leaves linear-lanceolate, subfal-cate, acuminate, 4.2-8 X 0.3-0.5 cm, abscissionlayer ca. 5 mm from base; inflorescence lateral, 8-9 cm, rachis fractiflex, bracts triangular-ovate, cor-date, acute, keeled, glandular-erose, 2-3 mm; ovaryand pedicel 6-7 mm; sepals ovate, carinate, apic-ulate, laterals reflexed, 3-3.2 X 2-2.2 mm; petalscuneate-unguiculate, truncate-subspatulate, 6 X5.6 mm; lip 9 X 3.2 mm, lateral margins recurved,callus 3 X 2.8 mm, cordate, ovate, distally contin-uous with surface of blade; shaft of column ca. 0.8mm, anther with rostellar beak ca. 3 mm. A single plant of this species was found by the
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