Revision of Agrostophyllum section Appendiculopsis (Orchidaceae), with notes on the systematics of Agrostophyllum

Section Appendiculopsis of the orchid genus Agrostophyllum is revised. Six taxa are recognized: Agrostophyllum elongatum, A. laterale, A. stipulatum subsp. stipulation and subsp. bicuspidatum, A. sumatranum and 1 A. trifidum. The status of a seventh taxon, A. ley tense, is uncertain. No new species are described here. Agrostophyllum celebicum Schltr. is reduced to A. stipulatum subsp. stipulatum, Poaephyllum hansenii J.J. Wood is reduced to A. laterale. The latter appears to be a strict rheophyte. All species are described and illustrated, and their phylogeny and ecology are discussed. The infrageneric classification and the systematic position of Agrostophyllum are reviewed.