This plant is listed as
Mule-Ear Orchid (Trichocentrum undulatum)
I'm not certain but I think it should be listed as Trichocentrum undulatum with Oncidium undulatum being a synonym.
Sources:
CATALOGUE OF LIFE:
Oncidium undulatum (Sw.) Salisb. Species synonym for Trichocentrum undulatum (Sw.) Ackerman & M.W.Chase
ITIS:
Trichocentrum undulatum (Sw.) Ackerman & M.W. Chase
Taxonomic Serial No.: 894691
Trichocentrum undulatum TSN 894691
Kingdom: Plantae
Taxonomic Rank: Species
Synonym(s):
Oncidium luridum auct. non Lindl.
Oncidium undulatum (Sw.) Salisb.
Oncidium maculatum (Aubl.) Ackerman
Lophiaris maculata (Aubl.) Ackerman
Trichocentrum maculatum (Aubl.) M.W. Chase