Definitions for "Laesura"
The scar on the proximal face of an embryophytic spore that marks the original contact with other members of the tetrad. It may be monolete, trilete, or rarely dilete. Pl. laesurae.
a ridge which surrounds the apertural slit (through which the gemetophyte germinates) in spores of Polypodiophyta; the shape of this ridge reflects the type of spore alignment in the tetrad. pl. laesurae.