A species from southern and central Africa named after John Sanderson (1820-1881), Scottish horticulturist and botanical collector in South Africa.
Grows epiphytically in in large clusters.
Pseudobulbs 3-5 cm apart, growing from a woody rhizome. Variable in size and shape, usually ovoid or pear-shaped, yellow, 2-leaved.
Erect inflorescence, up to 20cm long on a thick, swollen, rachis. Flowers 10-16, set alternately on either side of the rachis, essentially yellowgreen – sometimes heavily mottled with purple.