I am not sure what kind of weed this is, but the seed head provides a great graphical image. It'a amazing the detail you can see in a macro photograph that you cannot see with the naked eye! Shot in a light tent with two strobes.
Up here in Michigan we call it Buckhorn. That could be a local name. In any case, we have in our lawn, which indicates the soil is sour and I should apply some lime.
You're right about the fascination of close-up work, and the detail you can see. This is very nice!