To multiply a hybrid, and keep it identical to the parent plant, it must be reproduced vegetatively by taking cuttings or dividing a plant. I am going to discuss propagation by cuttings first.
Streptocarpus are a wonderful plant as they have the ability to reproduce themselves through single cell division due to the hormones (cytokinins) present in the leaves.
The part of the leaf that gets best results is near the base of the leaf. This is called the meristem (growing region). Remember this when taking cuttings as this part of the leaf will produce more plantlets earlier than the distal (end) of a leaf.
Always use a fresh, dark green leaf from near the center of the plant being propagated (around 4-6 inches in length). The older and yellowing leaves wont have the oomph they need to produce well if at all so avoid propagating them if possible.
When rooting the cutting use a sterile medium. My favorite is plain perlite. I also like using peat based seed starting mix with 50% perlite added to it. This gives you a nice 'airy' mix to help stave off rot. I then place the medium in my container and just wet it until it is barely damp. This is important as if it is to wet or heavy the cuttings have a wonderful chance of rotting.
I place my leaves just barely below the surface. I usually have to prop up the larger leaf pieces with a plastic name tag but I get more babies quicker this way. I also get less rot than if I bury the leaf deeper.
Place this in a bright location. I have to dome or bag mine to keep the cuttings turgid. I find it also helps to give it a little heat from below. I open my domes once a day to allow for some air circulation.
After about a month you should have roots developing...sometime sooner depending upon the vigor of the leaf and the cultural conditions.
Usually within a 2-3 more weeks you should have tiny plants growing from the base of the leaf where roots are growing.
After the first leaf of each baby is about 2 inches high I separate them. By this time they should have some roots of their own. If not I wait and keep checking until they do. You can pot them off the mother leaf earlier though if you wish. Just be sure to dome them if they show signs of wilt until they grow some roots.
While the baby is adjusting to its new pot it is important to go easy on the water. Keep the soil just moist but not to wet. Once the young plants are well established they can be potted into a larger pot.
Within 2-3 months most healthy plants should reach flowering stage.
Now for some pictures....
Here are the two main cuts I use when propagating by leaf cuttings.
I also like to cut strait across when not cutting out the vein as you will get babies from each vein that is cut and exposed to the medium....like on this cutting below.
Here is a leaf that I cut the vein out of.
Click here to see more pictures of leaves down in my albums.
I prefer to separate them when the babies are about 2 inches high as the babies usually have a few roots of their own by then.
I do this by pulling up the leaf from the propagation tray .
Holding onto the babies near the base of the cutting you pull gently and they usually come right apart at this stage.
Now you have the babies free from the mother leaf and ready to pot up.
I then keep them in an open greenhouse due to my low humidity until the first blooms....I then pot up and move them out into my normal house air.
I also have developed my own "lazy" way of propagation due to running out of space for keeping lots of extra babies around. I cut the leaf with the v type cut across and set this into a small pot. I then wait for babies to grow hoping for only one or two babies from the leaf. Once the babies are showing and looking good I cut the mother leaf off as close to the soil line as possible without harming the babies. I then let them grow on in the same pot....not potting up until first bloom. Here is a tray of babies I propagated in this way. When you are super busy this is a wonderful time saving way to do things if you don't mind more than one baby to a pot.
Here is the link to the Dibley Page for Propagation by leaf.
'Streptocarpus' by Rex Dibley as Reference.