Bert, I know that Rossioglossums were carved away from Odontoglossums due to the position of the lip but they didn't go far. All of these orchids are still in the Oncidium alliance and therefore, by definition, can be crossed or hybridized with each other. I also know that Rossioglossums are notoriusly hard to hybridize, even with each other, so there arn't very many floating around out there. I think Ros. grande was crossed with Onc. splendidum (also called Trt. splendidum) but that hybrid was never registered, thus no name. I found that a Ros. X Onc. is a Rossitolidium; a Ros. X Miltonia is a Rossitonia; a Ros X Miltoniopsis is a Rossitoniopsis and a Ros. crossed with a Brassavola is a Rothara. I don't trust that last one because normally a name ending in "ara" means is is a multi-hybrid of 4 or more genra. Potinara is a good example.
As for the word "tipo', it means "type" in Spanish and is often used as a subspecies or variety name. A good example is Cattleya bowringiana var. tipo.
I hope this helps.
Jim
