Rhynchospora filifolia A. Gray Rhynchospora filifolia A. Gray in Ann. Lyceum Nat. Hist. New York 3: 366-367. 1836 sec. González-Elizondo & al. 2018=Phaeocephalum filifolium (A. Gray) House in Amer. Midl. Naturalist 6: 181. 1920 syn. sec. Diego & González 2008