Jumellea arborescens H. Perrier 1938 GROUP 6
Plant and Flowers Photos courtesy of © Lourens Grobler
Side View Of Flower Photos courtesy of Danny Lentz©, plant grown by the Atlanta Botanical Garden
Another Flower Photo courtesy of Rod Rice and Oasis the Journal

To 
Common Name The Tree-Like Jumellea
Flower Size 2.4" [6 cm]
Found in central Madagascar in mossy forests on tree trunks at elevations around 1400 meters as a giant sized, warm to cool growing epiphyte or lithophyte with an elongate stem carrying in the apical half, to 20, fairly stiff, elliptic-oblong, bilobed apically, basally conduplicate leaves blooming on a short, axillary, erect, single flowered inflorescence enveloped below the middle by 3 to 4 loose sheaths.
References W3 Tropicos, Kew Monocot list , IPNI ; Angraecoid Orchids Stewart, Hermans, Campbell 2006