Yes! I get more off the ground than from the plants. The seeds are easy to spot--they look like little black hand-grenades.

A bit off topic, but you might also try saving the roots of 4 o'clocks and using them to start your plants. I saw that suggestion a few years back and decided to try it. I waited until the tops had frozen and then dug the roots. They look like ugly, black multibranched carrots. I stored those in dry peat in a plastic bag with a hole or two and put them in a cool closet. When I checked in the spring, they had all sort of green shoots. I replanted them and they took off quickly. They've increased in size each of the last three years--enough that they're almost too big for the only available spot.

Thanks Bitterwort for explaining to me how to store the root of my 4 O'Clocks. When I bought these the package was labeled Mirablis (sp). I had no idea they were 4 O'Clocks till they started leafing out. The plants got 4 foot tall and were so pretty with blooms!!! Next year I will need to stake them as they get so heavy with foliage and blooms the wind plays heck with them. I have already cut the stems down so I will have to get out there and dig up their roots and get them in peat.
Thanks again for your advice!!!
Marsha