PhalPal:
I'll try to help you with the Tolumnia/equitant question. There are a group of species, previously in the genus Oncidium, which have thicker, stiff leaves. These leaves, if cut to make a cross-section, are triangular in shape, thus the term 'equitant'. Recently, taxonomists have reassigned these orchids to the genus Tolumnia. Here's a link with information:
Equiatnt Oncidium or Tolumnia Orchids
Hope this helps!
jeanne