- Aperture in a plant - Leaf opening - Leaf pore - Small hole in plant leaf - One of the minute apertures between the cells in many serous
membranes. - The minute breathing pores of leaves or other organs opening
into the intercellular spaces, and usually bordered by two contractile
cells. - The line of dehiscence of the sporangium of a fern. It is
usually marked by two transversely elongated cells. See Illust. of
Sporangium.