A portion of leaf epidermis (PO:0006016) that covers the adaxial/upper surface of a leaf. [source: POC:Ramona_Walls]
Comment
Used to refer to an adaxial epidermis of an entire leaf. More specific terms exist for leaf lamina adaxial epidermis and petiole adaxial epidermis. If you are annotating to this term, please add an additional annotation to vascular leaf (PO:0009025) or non-vascular leaf (PO:0025075), depending on the species. All annotations for angiosperms, gymnosperms, and pteridophytes should go to vascular leaf and all annotations for bryophytes should go to non-vascular leaf.