This is an internet search that led here.
First, let’s remind what should be obvious but is apparently not realised by many people: since plants in general both have stamens and pistil(s), they are hermaphroditic. Of course, there are great variations with regard to realised gender in plant species, though, please go here for a short overview, but the most common situation is still hermaphroditism.
Orchids, as wonderful plants they can be, just follow this majority rule. One cannot be completely outstanding I guess. Indeed, as curious as it seems, orchids fairly rarely depart from possessing both male and female attributes at the same time, even if they indulge to quite strange sexual fantasies.
So the answer is straightforward: you don’t need to wonder if an orchid is male or female. There are good odds that they are both. And they are perfectly happy with this.
Catasetum orchids are dioecious, that is, evolved into full female or full male individuals from their hermaphroditic ancestors. This evolution path is quite frequent and occured many times independantly in plants, mostly as a way to avoid negative effects of selfing and inbreeding. But such negative effects are required for evolving the full separation of sexes. Not every species endures inbreeding depression nevertheless, and that’s probably why so many plants are still hermaphroditic and without making any issue about it. Many others have found their way to prevent selfing, dioecy being only one of them.
The trick is that once you evolved such a clear cut divide between maleness and femaleness, you must have some special agents willing to transport pollen to a safe place. Catasetum are pollinated by wonderful shiny bees, Euglossines, which pollinate a wide range of exotic plants in tropics.
And since I found a quite nice movie, I shall let you see it. That’s a male (oops, female) Catasetumbeing visited by marvellous greeny petsies:
Originally uploaded by Russian in Brazil