ABSTRACT:

Aridarum montanum Ridl. and Piptospatha insignis N.E.Br. (Araceae: Schismatoglottideae), aroids originating from Borneo that are each known from a single collection, are discussed and illustrated. The history of their discovery is reviewed, together with what is known or speculated of their ecology. The biological significance of the collection locality of A. montanum is highlighted. The species’ individual importance to modern systematics is highlighted.