Oncidium exauriculatum (Hamer & Garay) R. Jiménez 1992 SECTION Rostrata

Comparison shot of O exauriculatum and O cheirophorum

TYPE Drawing/Photos R Jimenez © and The Herbario AMO Website

EARLIER EARLY

Common Name The Without Ears Oncidium [refers to the lack of column wings]

Flower Size .32 to 52" [8 to 13 mm]

Found in Chiapas state of Mexico, Guatemala, El Salvador, Nicaragua and Costa Rica in montane rainforest at elevations of 700 to 1400 meters as a miniature to small sized, warm to cool growing epiphyte with clustered, ovate to sub-rhombic, strongly compressed, smooth, rugose with age, green often with purple spots which can be dense to be almost totally purple pseudobulbs carrying 1 to rarely 2, apical, sub-coriaceous, linear-elliptic to lanceolate, erect-arcuate, dorsally carinate, acute, basally conduplicate leaves that blooms in the earlier fall through early winter on 1 to 3, basal on a mature pseudobulb, erect to slightly arcuate, peduncle laterally compressed, from 2.4 to 6" [6 to 15 cm] long, paniculate, 2 to 4 branched, each branch .6 to 1.8" [1.5 to 4.5 cm] long, sometimes with secondary branches, 4.8 to 10.4" [12 to 26 cm] long, laxly, successively 7 to 28 flowered inflorescence with triangular, basally tubular floral bracts and carrying lightly scented flowers

Differs from the often cited as synomonous Onc cheirophorum by the lack of the aruricles of the column, geograpically, as it is not found in Panama and Colombia and in the autopollination of the flowers of Onc exauriculatum. O auriculatum also has mostly erect, paniculate, more spaced, less flowered inflorescence as well as successively opening flowers with a narrow stipe. Onc cheirophorum has large prominent auricles to the column, is found in Costa Rica, Panama and Colombia, is rarely cleisostogamus, arcuate-pendent inflorescence with many, simultaneously opening, clustered flowers which have a wider stipe

CAUTION Kew keeps this one as a synonym and variety of Onc cheirophorum but I, like R Jimenez, feel that it is substantially different and so I have kept its species status.

Synonyms Oncidium cheirophorum var. exauriculatum Hamer & Garay 1974

References W3 Tropicos, Kew Monocot list , IPNI ; Las Orquedias De El Salvador Vol 2 Hamer 1974 as O cheirophorum var exauriculatum drawing/photo fide; *Orquídea (Méx.) 12(2): 269-276. R Jimenez 1992. photo/drawing fide; Manual de Plantas de Costa Rica Vol 3 Hammel, Grayum, Herrera and Zamora 2003 as O cheirophorum var exauriculatum; Orchid Genera and Species in Guatemala Archila, Szlachchetko, Chiron, Lipinska, Mystkowska and Bertolini 2018

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