This is my first year collecting them, so I don't know if they grow true. The seed pods were about an inch long and pointed, with a ball at the base. There were not a lot of pods formed. Sorry I can't do pictures, my plants are dead now. There was 1-3 seeds per pod. I waited until they were brown to collect them.

I have had white for several years that comes true, but it sets far fewer seeds than the other colors and does not self sow for me, as the others do. It is at least 150 feet from my other Thunbergia alata. I am sure cross pollination would take place if they were closer.
I also grow a mix that I purchased a few years ago that encompasses cream, terra cotta, and orange colors. I still have all of the colors, but it seems that each year the balance tips toward the orange.
Below is a photo of the covering that sheaths the seed pod, and another of the exposed seedpod. Not every flower produces seeds so you have to hunt around for them. They will turn brown when ready to harvest. If you pick them whole and put them on a plate to open later, you may come back and find that you have nothing. They pop open vigorously and the seed is dispersed through the air.

Hi. I have the yellow black-eyed susan vine, and I really love it for its bright flowers and rapid growing habit. I have been collecting seed pods - I have only had the plant since this spring, and I'm not sure if these are really the seed pods. They look like little balloons, and I think there is one for every blossom. Mine are usually green when I take them off the vine, and I save them in paper. Hopefully they will turn out to be viable next spring because I would like many more plants.

The first time I collected the seeds I didnt realize they would pop out of those pods. I had been collecting them just before they opened and keeping them in a butter tub on the kitchen counter. I kept thinking my kids were messing with them because I would find the seeds all over the counter. Turns out the seeds actually have a mini-explosion propelling the seeds out of the pod. I realized this after finally hearing them pop.

Can you pick the pods when they are green? or do you have to wait for them to turn brown? I could put them in an explosion proof container! :-D