Prickly husks are a type of seed covering that is made up of small, sharp spines. They are also known as burs or burrs, which are the solutions to the crossword clues. Burs are typically found on plants such as burdock, thistle, and teasel, while burrs are usually found on plants such as cocklebur and beggar-ticks. These prickly husks can easily attach to clothing and fur, making them difficult to remove.