Wet woodland plant for ID

Wet woodland plant for ID

Observation - Wet woodland plant for ID. Description: I know this is a difficult one. This plant doesn't seem to have many distinguishing features. I have never seen it flower. It grows in dense patchy clumps in fairly deep shade provided by Sweet Chestnut. It only grows in the wettest part of the valley. Al

I know this is a difficult one. This plant doesn't seem to have many distinguishing features. I have never seen it flower. It grows in dense patchy clumps in fairly deep shade provided by Sweet Chestnut. It only grows in the wettest part of the valley. Also here are Broad Buckler Fern,Elder and Arum maculatum. Sandy, acid, damp, shaded woodland. Thanks for looking any clues will be appreciated.