Paspalum (Poaceae, Panicoideae) is a large genus comprising approximately 330 species, of which 210 are cited for Brazil. Paspalum minutispiculatum is similar to other related species of the informal “Humboldtiana” group, but this new species is annual and lacks rhizomes. This work establishes the distinction between this new species and related ones from this group, and contributes to a better characterization of the little known P. bicilium. Micromorphological characters of the upper anthecium and anatomical characters of the root, culm, and leaf of both species were analyzed. The new species appears to be endemic to the Federal District. It grows along trails in gallery forest, which is a rare habitat for this genus. The present work includes a key for species of the “Humboldtiana” group.