AbstractAn introduction is given to the tropical moss family Calymperaceae, including a description of its characteristic hyalocyst pores. Keys (for both fertile and non-fertile collections) are provided to the genera, subgenera and sections found in West Tropical Africa. A revision ofCalymperesis given for that region, with a key to the species and subspecies. The peculiarities of the genus (teniole, parateniole, extrateniolar lamina, endohyalocysts, exohyalocysts, leaf polymorphism and foliar gelnmae) have given rise in the past to much confusion and a large synonymy, and the taxonomic implications of these characters are discussed.