Sort of folder seen in the autumn? (5-4)
I believe the answer is:
loose-leaf
'sort of folder' is the definition.
I cannot understand how the remainder of the clue works.
(Other definitions for loose-leaf that I've seen before include "(Of a folder) with removable sheets" , "With pages that can be easily rearranged" , "Like some folders" , "Allowing the insertion and removal of pages" , "Describes binder with allows addition and removal of pages" .)