Small sticky whitish ball. what are they? I don't know how else to describe these things... other than small...

I don't know how else to describe these things... other than small sticky whitish balls. LOL. When I be a child I would get these things (possibly seeds?) stuck on the tops of my socks when I go hiking. They are very small- about 1/4 the size of a pencil eraser, and they are sticky, somewhat thorny, little whitish ball. They get stuck in my cat's fur when she go outside. What are these things?
Landscaping the backyard?
Answers:    Maybe galium apparine--also called cleavers, sticktights, or sticky willies.
http://www.missouriplants.com/Whiteopp/G...
How to trim a dogwood tree undamagingly ?
small burrs. They are seeds.