Gallium aparine : Bobby Buttons, cleavers, catchweed, whippysticks: so many names. Sticky Willy is my favourite. I spent summer once with cousins in Govan. We did actually see the countryside, it was a bus ride away and guess who got "sticky wullie" stuck on the back of his jumper. Other than that, I made it all up - but you knew that anyway. Image is PD from wiki commons.