A bright field, multi-focus stack image of a sorus of Asplenium trichomanes (maidenhair spleenwort), a small fern.

A bright field, multi-focus stack image of a sorus of Asplenium trichomanes (maidenhair spleenwort), a small fern. A sorus is a cluster of sporangia, which produce and contain spores

Photo credit: Gerd Guenther