I have learned something – “bracken” is always ferns.

• 06.041 among the bracken
• 06.045 At times they were pushing through a sea of bracken
• 06.070 Yellowing bracken, fallen branches,
• 06.072 and bracken.

“bracken, n.1.” OED Online. Oxford University Press, June 2015. Web. 28 July 2015.