Unknown plant, unknown location, no pic and a minimal description. If someone nails this they will have my undying homage.

tj

I agree...you gotta do better than that, Jon. ;-)

Aphids congregate on the underside of collards and other 'greens', but that is purely a wild guess, given the lack of information.

The eggs of various insect species also come to mind.

I can promise you that if you come up with some pictures or even a good description, someone here will be able to ID what might be on your collards.

Jon987, you can also search Leaf spots on collard and you might see some matching images.