<i>Cyperus microspermus</i> (Cyperaceae), a new species from South America

A new species of Cyperus from South America, belonging to C. sect. Haspani, is described and illustrated. Cyperus microspermus is morphologically related to C. tenuispica, C. bampsii and C. haspan, but can be differentiated by the following characters: involucral bracts never exceeding the inflorescence length, spikelets solitary or rarely in pairs in the branch tips, glumes imbricated, stamens two, achenes obovoid‐ellipsoid with a truncate base. Besides the morphological description, we discuss achene micromorphology as a diagnostic character. We also provide a preliminary assessment of the conservation status, and information about geographical distribution, habitat and phenology.