Emerald Clump Moss

This gray-green moss is commonly found growing in giant clumps On trees, and On rotten logs.
It is short, growing up to 2 inches (5 cm) tall. It forms in extensive patches and they overwhelm an area rapidly, and is extremely rigid; it struggles more than most during dry spells.
When mature, emerald kidney-shaped capsules grow at the end of elongated, lime green sporophytes, eventually opening up during the mid-autumn to release hundred of spores; it can cause allergic reactions.