Brownfern

This brown moss is commonly found growing in small clumps In heathlands, and On trees.
It is giant, growing up to 1.3 feet (38 cm) tall. It forms in sparse patches and can overwhelm an area rapidly, and is slightly sturdy; it is very difficult to kill.
When mature, emerald triangular capsules grow at the end of elongated, lime green sporophytes, eventually opening up during the early summer to release dozens of spores.