I can't see the pistols or stamens in my bloom. How do I cross them? How long does it take a seed pod to ripen?
Sometimes they are hard to see, but you can trim part of the flower away to expose them. The pod takes a few months to turn brown and mature. Good luck.
There should be one long-ish spike looking thing in the flower, green near the base, with a white-ish tip. That's the style, ovary, and and stigma. All together they are called the pistil. It becomes more obvious as it matures, usually after the flower is a few days old.
When the flower is newly opened, you should be able to see a few little yellow things on thinner threads in there. Those hold the pollen. They tend to retract and hide as the flower matures.
The trick is to get fresh powdery pollen from a newly opened flower, and brush that on a mature stigma in a flower a few days old.
As greenthumbgardener mentioned, cutting away the flower corolla (petal) can make them easier to find. You do have to be careful not to cut the style though. I usually gently pull off the corolla of the seed parent before it opens and releases pollen, so I can see when the stigma is mature. The pollen comes off with the flower tube.
It's hard to describe without pictures, but not hard to do once you get it.
A pollinated Strep will start growing a long thin seed pod, which will start showing its typical spiral after a week or so. When it turns yellowish or brownish and starts to split, you can cut it off to dry the seed, and be ready to plant.
In case you didn't already know, Streptocarpus (and African violet, and almost all other gesneriad) seed is extremely fine, almost dust-like, and should not be covered when planting.
Streps have their own set of traits that can come through or not in a cross. One basic thing is that blue/purple colors are dominant over most other colors. That also means a blue colored flower can hide almost any other color- which may come out in up to 25% of the seedlings when crossed with another blue color, or up to half the seedlings if crossed with say, a pink or red.
The genetics of the newer variegated and fragrant varieties isn't as fully understood. Once thought to be inherited only through the "mother" (seed) side, I've heard that variegation has shown up from the pollen side too. Fragrance is unpredictable and can come from either side, and may not smell like either parent.
I'm personally interested in breeding ever more compact, even miniature Streps, but have only recently gotten back into breeding, so barely have the first cross done in that direction yet. I have very little hopes ;)