Slow passive nastic annulus movement and fast relaxation entailing spore ejection. Note that spores adhere to both cups during the tensioning movement and do not yet become shed. The sporangium was gripped with tweezers (real-time MOV, 20 fps, 400 x 200 pixels, 142 KB).
Poppinga S, Haushahn T, Warnke M, Masselter T, Speck T
CC BY 4.0
<a rel="nofollow" class="external text" href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4596474/bin/pone.0138495.s006.mov">S5 Video</a> from <cite style="font-style:normal">Poppinga S, Haushahn T, Warnke M, Masselter T, Speck T (2015). "<a rel="nofollow" class="external text" href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4596474">Sporangium Exposure and Spore Release in the Peruvian Maidenhair Fern (Adiantum peruvianum, Pteridaceae)</a>". <i>PLOS ONE</i>. <a href="https://en.wikipedia.org/wiki/Digital_object_identifier" class="extiw" title="w:Digital object identifier">DOI</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1371/journal.pone.0138495">10.1371/journal.pone.0138495</a>. <a href="https://en.wikipedia.org/wiki/PMID" class="extiw" title="w:PMID">PMID</a> <a rel="nofollow" class="external text" href="https://www.ncbi.nlm.nih.gov/pubmed/26444002">26444002</a>. <a href="https://en.wikipedia.org/wiki/PubMed_Central" class="extiw" title="w:PubMed Central">PMC</a>: <a rel="nofollow" class="external text" href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4596474">4596474</a>.</cite>