@Betty in Texas: Mule ear oncidiums belong to a class of oncidiums with very diminutive pseudo-bulb bearing a single broad, mule ear shaped leaf(thus the name) anywhere from 2 - 10 inches long. Flowers are typically oncidium-like, and mostly coloured in shades of brown and yellow.Many are quite fragrant. A typical example is Onc lanceanum.(You can google for pix of them).
Many people have moved mule ear oncidiums to the genera Lophiaris or Trichocentrum, but old-timers like me still refer to them as oncidium.
By the way, there are also rat-tail oncidiums, equitant oncidiums and the goldiana -type leaf oncidium( the 'normal' oncidium type plant which also resembles miltonia). Of course equitants are now Tolumnia and rat-tails are.............( can someone please tell where they have been moved to?)