Orchid genetics are extremely complicated. They are one of the VERY few things that can be crossed inter-specially, inter-generically - and in one case I've studied (Cym. X Ctsdm.) inter-tribally. Plants with very different pollinators can be grown touching and a breeze can cross them. This is extremely rare and usually pointless as they die out. Speaking of millions of years, if it only happened once per decade, there will be hundreds of thousand of such crosses in the wilds.
When you have some of the multi-generic hybrids (some of the -aras have many genera included) that are usually viable, the result becomes the largest classification known. Even a usually sterile cross will often have one or two that are viable.
__________________
Tomorrow is the price of yesterday - Bob Seger
|