Last year I bought a moss rose at the market. The little pot must have contained three separate moss roses as it blossomed in white, yellow, and pink. In autumn I collected the seeds, stored them in a paper bag, then sowed them in spring.
At first they were measly little things that suddenly stopped growing at a height of about 1 inch. The guy at the market stall said they should have been exposed to frost because otherwise they don’t get “activated”. Which I guess can’t be entirely true, because…
… suddenly, only a couple of weeks later, they shot up, grew into little moss rose bushes, and started to produce flowers. From what I’ve gathered so far, at the top of each plant are three seed pods. They flower one after the other, and if one wilts, you pluck it off to make space for the new one. When the last one is done, you can gather the seeds. One of the white plants keeps producing white flowers with a single pink petal.
These moss roses are a complete joy with hardly any work at all, except for removing wilted flowers. I will definitely collect seeds again this year, although probably storing them in separate paper bags according to colour.
BTW – for the close-ups of the yellow one, I used a (borrowed) extension ring on my (also borrowed) 60 mm lens.