Where exactly in South America?
Is the garden outdoors or under glass?
If outdoors and in the north within a reasonable proximity to the Caribbean it may very well be an Encyclia. If it's indoors, then it could be either. Many Epi's and Encyclia's are similar looking at first blush.
To my eye that flower in your picture looks very close to an alba form Encyc. randii.
What did the plant itself look like?