OK, Now the real question: How can an orchid self-pollinate before the buds open?
 

I assume it is caused by a structural defect such as the anther cap and/or the filament attached to the pollinia not forming correctly.

Anyone know for sure, or just have thoughts on it?

Cleistogamy

Known to occur in Zygopetalums and Guarianthe aurantiacum amongst others.

I have also heard that Phragmipediums have a tendency to self-pollinate, so it is important to remove the pod plant pollinia before attempting hybridization.

There are a fairly large number of cleistogamous orchid species in Puerto Rico. Unlike chasmogamous (open or showy) orchid flowers, the cleistogamous flowers have a high rate of reproductive success. It's the Woody Allen version of plant sex, but apparently it works!

Thanks folks.
I have learned 2 new words today.
Cleistogamy and chasmogamy.
Never really had the need to know them before, but I certainly do now.

But, neither of those answer my question they are just names for the state of being of each of the conditions.

I do not expect anyone here to have a factual answer for my question, but I have to ask it anyway, so to rephrase it:
What makes an individual plant from an orchid species that normally produces chasmogamous flowers to produce cleistogamous flowers?
my assumption is that there is a genetic mutation that causes the normal flower structure for that species to be modified somehow in the aberrant individual.
My assumption is that something like the anther cap is missing or defective and/or the filaments that attach the pollinia may be missing or defective, or some other physical change that would allow the pollinia to contact the stigmatic surface causing self pollination.

Any information or thoughts on this?

Hi voyager

Your assumption that the flower morphology changes in cleostigamous flowers is correct. The exact change probably is different for different orchid species, and I am far from an expert on the individual mutations or adaptations that allows self a pollination to occur. This is one of those "more than one way to skin a cat" sort of problems. When you see orchids that are less showy, don't seem to attract pollinators, havecno pollination reward (nectar, etc.), yet set seed capsules anyway, there is a good chance the orchid is self-pollinating. Especially when the above characteristics are combined in one plant.

If there is a particular orchid species that you see self-pollinating, you can Google the species name and cleistogamy together, you might find that some botanist has researched the pollination mechanism already and has described it in a publication.

Cleistogamous or not, I don't think an unopened bud is mature enough.

I have Datura wrightii, a beautiful Sonoran Desert perennial angel's trumpet. My strain is a cultivated strain. The flowers have all the parts. The anthers of open flowers seem to have no pollen at all, even when I cut them apart. Every flower produces a large fruit full of viable seeds. I have queried Sonoran Desert botanists; they tell me this species is known for self-pollination, which usually occurs before the flowers open.

I have been too lazy to ever go out and cut open a nearly-ready-to-open-bud, but maybe one of these days I'll get a round tuit.