Emerald

This emerald moss is commonly found blanketing large areas In marshes.
It is small, growing up to 1 inch (3 cm) tall. It forms in sparse patches and they overwhelm an area rapidly, and is extremely strong; it can easily endure being trodden on.
When mature, emerald triangular capsules grow at the end of long, lime green sporophytes, eventually opening up during the late autumn to release thousands of spores; it can cause severe allergic reactions.