Fern sorus. Fluorescence light micrograph of a sorus on the underside of a fern frond. A sorus is a cluster of spore-producing receptacles called spor

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Fern sorus. Fluorescence light micrograph of a sorus on the underside of a fern frond. A sorus is a cluster of spore-producing receptacles called sporangia. Each sporangium is packed with spores, which are the fern's reproductive cells. A rim of thick-walled cells, the annulus, functions to open and rapidly close each sporangium when the spores are mature, releasing them into the environment.

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Size: 6000px × 4000px
Photo credit: © FRANK FOX/SCIENCE PHOTO LIBRARY / Alamy / Afripics
License: Licensed
Model Released: No

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