Ledermanniella yiben sp nov (Podostemaceae), Critically Endangered at the proposed Yiben Reservoir, Sierra Leone

Ledermanniella yiben Cheek is described from the Seli (Rokel) river bed at a single rapid to be flooded by the proposed Yiben hydroelectric dam and reservoir in Sierra Leone. It is assessed as Critically Endangered using the IUCN categories and criteria. The species appears to be unique among African Podostemaceae in bearing dimorphic shoots having either cupuliform or short ribbon-like leaves.