Um, the seeds are always located in the flowers.

That said, the flowers are not always where you expect them to be. Strawberry seeds are on the outside of the fruits, tomato seeds are on the inside, sunflower seeds are in the center of the flowers, balsam seeds are enclosed in pods.

Perhaps if you discussed your reason for wanting to know, it might help. For example, if you are just trying to increase the number of existing plants, divisions or cuttings may work much better than collecting seeds from them.

walk up to each plant.. and feel it up ...

if you find a hard coated thingee.. its probably the seed...

pix of dormant plants can be IDd in the name that plant forum ....

and general advice given.. thereafter ...

most likely.. you need permission to trespass on any given property ...

it would be much easier.. to buy seed packs at the local tractor supply or hardware store ... no one is that rural.. that you dont have a seed seller nearby

ken