A fern is a member of a group of about 10,560 known extant species of vascular plants that reproduce via spores and have neither seeds nor flowers. They differ from mosses by being vascular (i.e. having water-conducting vessels). They have branched stems and leaves, like other vascular plants. These are megaphylls, more complex than the simple microphylls of clubmosses. Most ferns have what are called fiddleheads that expand into fronds, which are each delicately divided.