Sunflower seeds that I saved

About mid-summer, we noticed a lone sunflower growing in the soybean field behind our house. Since no one in the area has sunflowers, we guessed that a bird must have sown it from seed in our feeders (or some other source). It was about 30 feet out into the field, and we had just had a rain, so it was pretty muddy. I wanted to go out and get it, and put it in our garden, so I put on my sandals and started out. I had neglected to notice that where I was walking was also where we dumped the dirty cat litter. Oh well, the sandals were rubber and would hose off easily. Yeah, right. I think I've come up with a new recipe for hypertufa. Ohio clay + rainwater + kitty litter + stuff that you throw out with the kitty litter. OMG. Well, anyway, that's not what my question is pertaining to.

I got the sunflower, planted it, and it thrived. Only one large head, but several smaller ones. I let it dry and I just now went out and brought in the large head to get the seeds from it for next year. The smaller ones never developed enough to produce seed. I got a fair amount of seeds from the large head, and they're really small. The sunflower plant itself was about 3 feet tall, and the seed head was about 2½ - 3 inched in diameter. The seeds are a little smaller than popcorn kernels, and more flat of course. I'm hoping they will give me lots of sunflowers next year. Do I need to do anything special with them? And what kind of sunflower might it be that has such small seeds?

It could be one of the wild flower perennial ones that grow. Not sure of any names. You could put Helianthus in the plantfiles and look for a similar one or Google and select images.