Unlike the other two perennial Cyperus species (longus and eragrostis) which can be about 1 m tall, Cyperus fuscus is a small insignificant little annual plant easily overlooked. This one was no more than 10 to 20 cm tall and in a ditch. Only when it was pointed out did I even see the flowers.

It is a national rarity and only occurs in a few places in Southern England and is absent from Wales, Scotland and Ireland.