Pleurothallis arcuata Lindl. 1859 SUBGENUS Effusae Luer 2000
Photo by G Chiron and Notes sur un groupe brésilien de Pabstiella (Pleurothallidinae, Orchidaceae) Chiron & Ximenes Bolsanello Richardiana X[2] Mars 2010
Drawing by Carl Luer
LATE 
to EARLY
Common Name The Bow-Shaped Pleurothallis [refers to the fractiflex inflorescence]
Flower Size 1/5" [.5 cm]
Found Brazil, Venezuela, Guyana and Peru in open montane forests to high mountain ridges in shady and humid areas of the southeastern Atlantic forest at elevations of 1000 to 1600 meters as a small sized, cool growing, caespitose epiphyte with an erect ramicaul enveloped basally by an elongate, tubular, evanescent sheath and carrying a single, apical, erect, coriaceous, elliptic-oblanceolate, obtuse leaf that blooms in the late spring and early summer on to sometimes 2, arising through a thin spathe at the base of the leaf, peduncle 4 to 10" [10 to 25 cm] long, distichous, slightly flexuous, 8 to 18" [20 to 45 cm] long overall, very loosely, several to many successively flowered, racemose, fractiflex inflorescence with shorter than the pedicel floral bracts and carrying non-resupinate flowers.
"Characterized by the stout ramicaul shorter than the elliptical leaf. The loosely flowered inflorescence far exceeds the leaf. The pedicel and ovary are elongated, bearing the flower in a non-resupinate position. The middle sepal is ovate and acute, expanded above the concave base with the sides only slightly recurved. The synsepal is contracted and concave below the middle between erect sides above which the sides recurve slightly . The petals are three lobes with the apex and marginal lobees rounded. The lip is thick and arcuate with a pair of calli within erect margins, the apex is verruculose and the base is bilobulate. Similar to P alligatorifera differs in having shorter pedicels and ovaries, a narrower and thicker middle sepal that is deeply concave below the middle betwween thickened sides and fleshy thickened above the middle to a rounded apex and petals with an acute apex." Luer 2000
Synonyms Effusiella arcuata (Lindl.) Baptista 2011; Humboldtia arcuata (Lindl.) Kuntze 1891; Humboltia arcuata (Lindl.) Kuntze 1891; Lepanthes chrysosepala Barb. Rodr. 1882; Pabstiella arcuata (Lindl.) Luer 2007; Pleurothallis arcuata var. parvifolia Cogn. 1906; Pleurothallis ocellata Porsch 1905; Pleurothallis rhombipetala Rolfe 1893; Specklinia arcuata (Lindl.) Luer 2004; Stelis arcuata (Lindl.) Pridgeon & M.W.Chase 2001
References W3 Tropicos, Kew Monocot list , IPNI ;
*Fol. Orchid. 9: 84 Lindley 1859;
Gen. Spec. Orchid. 2: 44 Barb. Rodr. 1881 as Lepanthes chrysosepala;
Revis. Gen. Pl. 2: 667 Kuntze 1891 as Humboltia arcuata;
Bull. Misc. Inform. Kew 1893: 4 Rolfe 1893 as P rhombopetala;
Oesterr. Bot. Z. 55: 157 Porsch 1905 as P ocellata;
Flora Brasilense 3(6): 559 Cogniaux 1906 as Pleurothallis arcuata var. parvifolia;
Iconographia de Orchidaeceae Do Brasil Hoehne 1949 drawing fide;
Flora de Venezuela Foldats Volumen XV Part 2 1969 as P rhombipetala;
Fieldiana Biology, Vol 33, 1st Supple. to the Orchids of Peru Schweinfurth 1970 not = P fornicata;
Orchidaceae Brasilensis Band 1 Pabst & Dungs 1975 drawing ok;
Icones Pleurothallidinarum Vol III Systematics of Pleurothallis Luer 1986;
Orchids of the High Mountain Atlantic Rainforest in SE Brazil Warren & Miller 1994 drawing good;
Lindleyana Vol 16 No 4:261 Pridgeon & M.W.Chase 2001 as Stelis arcuata;
Icones Pleurothallidinarum Vol XXVI Pleurothallis subgenus Acianthera and Three Allied subgenera, A Second Century of new Species of Stelis of Ecuador, Epibator, Ophidion and Zootrophion Luer 2004 as Specklinia arcuata;
Icones Pleurothallidinarum Vol XXIX A Third Century of Stelis of Ecuador Systematics of Apoda-Prorepentia Luer 2007 as Pabstiella arcuata;
The Organ Mountain Range Its History and Its Orchids Miller, Warren, Miller and Seehawer 2008 drawing good;
Mille et Une Mini Orchideees Roguenant 2009 as Stelis arcuata photo fide;
Colet. Orquídeas Brasil. 9: 337 Baptista 2011
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