This volume contains two papers
1. M.E. Minderhoud & E.F. de Vogel, A taxonomic revision of the genus Acriopsis Reinwardt ex Blume (Acriopsidinae, Orchidaceae)
This article presents a taxonomic revision of the genus Acriopsis (6 species, 5 varieties). One species (A. gracilis) and one variety (A. javanica var. auriculata) are described as new. Two species are reduced to variety level (A. javanica var. floribunda, A. densiflora var. bomeensis). Twelve names are reduced to synonymy.
2. E.F de Vogel, Revisions in Coelogyninae (Orchidaceae) II: The genera Bracisepalum, Chelonistele, Entomophobia, Geesinkorchis, and Nabuluiao
This paper embraces a taxonomic revision of the genera Bracisepalum (2 species), Chelonistele (11 species, 4 varieties), Entomophobia (1 species), Geesinkorchis (2 species) and Nabaluia (3 species). Synonymy, descriptions, distribution, habitat notes, and colour descriptions are given; each species is illustrated by a figure. Keys are given to the species.