* A generally dorsi-ventrally flattened organ, usually functioning in photosynthesis and transpiration, either gametophytic (in mosses and some liverworts) or sporophytic (in vascular plants), often variously modified. (plant part) | * A generally dorsi-ventrally flattened organ, usually functioning in photosynthesis and transpiration, either gametophytic (in mosses and some liverworts) or sporophytic (in vascular plants), often variously modified. (plant part) |