Leaves of edelweiss protect from cold via woolly hairs.
“Cold remains a major danger, for the temperature even in summer may fall well below freezing at night. A furry blanket can help to keep off the worst chills. The edelweiss, growing in cracks in rocks, protects itself with a coat of woolly hairs that gives its leaves and the bracts surrounding its tiny flowers a felt-like appearance.” (Attenborough 1995:253)