I think the name of the plant that you're after that sticks to your clothes is called goosegrass. I remember as a child I'd come home covered in the seeds and leaves of goosegrass and not have the faintest idea how it got there!
The scientific name for goosegrass is gallium aparine, but it's also got loads of nicknames, including clivers, catchweed, stickyweed, robin-run-the-hedge, sticky willy and grip grass. I personally think that stickyweed is the most appropriate title!
Why does goosegrass stick to clothing?
The little flowers on goosegrass are covered in hooked hairs, which is why they stick to clothing so easily. They're also a pain to remove from animal fur!
Skin irritation
Some people experience a nasty rash if they come into contact with goosegrass. This is known as contact dermatitis.
This guy uses goosegrass within his food recipes. I'm not sure it's something that interests me a great deal, but still, it's pretty interesting that people make use of things most of us would consider a nuisance.