Resurrection of Carex ignota (Cyperaceae, section Laxiflorae), a long overlooked sedge of the southern U.S.A.

Abstract

Since its publication in 1849, Carex ignota has been overwhelmingly ignored or treated as a synonym of C. striatula. Here, I present results of statistical analyses that support C. ignota as morphologically distinct from C. striatula and designate a lectotype for C. ignota. I also present the geography of C. ignota and C. striatula from over 750 examined and georeferenced specimens and results of maximum likelihood phylogenetic reconstruction of ddRAD loci. Carex ignota is distinguished from C. striatula by its narrower leaves on vegetative shoots, more loosely-flowered pistillate spikes, staminate spike with longer peduncles, and narrower perigynia. Based on strong morphologic and molecular evidence, C. ignota should be resurrected and treated as a distinct species. Carex ignota occurs on the Coastal Plain in the southeastern United States, as well as northern Alabama, the Ouachita in Arkansas, and the Piedmont in Georgia, where it grows in sandy to loamy soils in ravines and on slopes in mesic deciduous or mixed hardwood-conifer forests.