Abstract
Recent collections of the Tropical to Subtropical Australian endemic species Fissidens darwinianus with good fruiting material have enabled an elaboration of the type diagnosis with a complete description of the sporophyte and updated anatomical details. The peristome is of the bryoides-type. Fissidens darwinianus appears closely related morphologically to F. bogoriensis, a species known from China, Japan, the Malay Peninsula and most of the large islands of the Indo-Pacific as far east as New Guinea. The relationships of F. darwinianus to the globally widespread and morphologically diverse F. curvatus are being further investigated.