‘Cliff brake’ fern

This species: “Pellaea viridis.”
In this image, the leaves or fronds are edged with sori (plural form of “sorus”). From britannica.com, a sorus is a “brownish or yellowish cluster of spore-producing structures (sporangia) usually located on the lower surface of fern leaves.”

Species page at PhytoImages, http://phytoimages.siu.edu/cgi-bin/dol/dol_terminal.pl?taxon_name=Pellaea_viridis&rank=binomial

Photo taken at SIUC Plant Biology Greenhouse, http://www.plantbiology.siu.edu/facilities/plant-biology-facilities/greenhouse/index.php

1 year ago (“Back in our garden”): http://365project.org/rhoing/365/2013-04-29
2 years ago (“A 3-frame day”): http://365project.org/rhoing/365/2012-04-29
3 years ago (“Respite”): http://365project.org/rhoing/365/2011-04-29