Sledge (1981) described the fern Trigonospora obtusiloba Sledge (1981: 18) of Thelypteridaceae as a new endemic species from Sri Lanka. Fraser-Jenkins (2008: 595) suspected that this species was a probable synonym of Cyclosorus caudipinna (Ching) Panigrahi (1993: 66) but it differs from C. caudipinna in smaller size and lack of caudate pinnae apices (Sledge 1981). It can further be distinguished by its strongly dimorphic fronds, i.e., fertile fronds have narrower pinnae and longer stipes than sterile fronds. This is clearly evident in all specimens listed below and has not been reported from any other species of Cyclosorus subgenus Trigonospora (Holttum) Panigrahi (1991: 13). Since the opinion of Fraser-Jenkins (2008) is not supported, it is logical to maintain T. obtusiloba as a distinct species until further molecular data clarify its position. According to present generic concept of Thelypteridaceae (Christenhusz et al. 2011, Rothfels et al. 2012) T. obtusiloba should be transferred to Cyclosorus Link (1833: 128) and consequently a new combination under Cyclosorus is proposed here.