Catasetum rectangulare GFCarr

Published originally and reproduced here with the permission of the Orchid Review, volume 114, no. 1267, Jan-Feb 2006, pages 32-33.

CATASETUM RECTANGULARE G.F. Carr sp. nov.
Summary
A new species of Catasetum L.C. Rich from Colombia, found in cultivation, is described.

Catasetum rectangulare G.F. Carr sp. nov.
TYPE: Colombia, locus incertus, flowered in cultivation 2005 from a group of plants originating from Colombia. With the help of Sr. Francisco Villegas Velez of Orquifollajes in Medellin, Colombia, it appears that this flower matchs that of a plant found the eastern Colombian Department of Arauca; however this identification cannot be stated as positive from photographs without comparing type specimens. Supplied by Mrs. Mercedes V. Steuerwald s.n. (Holotype: USF).

Latin diagnosis: Species haec Cataseto calloso Lindl. similes sed labello anguste rectangularis et sepalis lateralibus latis falcatis differt

Plant epiphyte. Pseudobulbs caespitose, fusiform, 6-8 cm long. Leaves not seen.
Inflorescence, male, arching from base of pseudobulb to 25 cm long. Flowers male,10, pale chartreuse yellow. Labellum vertically rectangular with distal triangular extention, slightly denticulate on sides, shallowly saccate 0.4 cm deep, 1.7cm long, 0.6 cm wide. Dorsal sepal erect, slightly concave 3.1 cm long, 0.6 cm wide. Lateral sepals falcate, slightly cupped, 2.7 cm long, 0.7 cm wide. Petals erect, convex to parallel and overlap margins of dorsal sepal, 2.5 cm long, 0.5 cm wide. Column arching, fleshy, 1.5 cm long, 0.6 cm wide with antennae 0.7 cm long, parallel extending over upper edge of lip, passing on each side of small central callus on lip. Female flower not seen.

Observations: Distinguished by the vertically rectangular lip and the falcate lateral sepals.

Background comments: On February 26, 2005, Mrs. Mercedes V. Steuerwald brought to the American Orchid Society West Palm Beach Judging Center a plant that had been purchased at the Miami International Orchid Fest tagged as Catasetum poriferum “alba” (sic.). A Certificate of Botanical Recognition was granted, an award that requires taxonomic verification. When the author received the flowers preserved in spirit, they were compared to the type description of Catasetum poriferum Lindley (Edwards's Botanical Register (28) 1838 Misc. 89). A copy of the drawing of the labellum of the type was obtained for comparison from the Kew Herbarium. These flowers did not match the type of Ctsm. poriferum and so they were compared to other species Catasetum especially those of the Catasetum callosum complex to which this species appears to belong. None of these species had the rectangular lip and falcate lateral sepals of this flower. It was established that the plant had come from Colombia. There are what appear to be a colored form similar to this species among the pictures in NATIVE COLOMBIAN ORCHIDS, volume 1 and an album form in volume 5 but they are erroneously identified as Catasetum callosum. Both of these pictures lack the strongly falcate lateral sepals of this species.